JP2005044833A - Board with built-in electronic part, method of manufacturing the same and semiconductor package - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a board with a built-in electronic part which is small in size and has a built-in capacitor of large capacity, to provide a semiconductor package using the same, and to provide its manufacturing method. <P>SOLUTION: The board 1 with a built-in electronic part is equipped with a resin board 21 and a laminate 10 provided on its one main surface. The laminate 10 is equipped with a first conductor pattern 11b opposed to the main surface of the resin board 21, an inorganic dielectric layer 14b interposed between the resin board 21 and the first conductor pattern 11b, and a second conductor pattern 12b interposed between the resin board 21 and the inorganic dielectric layer 14b. A part of the laminate 10 constitutes, at least, a capacitor 50, and the inorganic dielectric layer 14b is formed through a sol-gel method. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component built-in substrate, a semiconductor package, and an electronic component built-in substrate manufacturing method, and more particularly, to an electronic component built-in substrate incorporating a capacitor, a semiconductor package using the same, and an electronic component built-in incorporating the capacitor. The present invention relates to a method for manufacturing a substrate.
[0002]
[Prior art]
Up to now, improvements in performance and reductions in size, thickness, and weight of electronic devices have been achieved by making semiconductor packages smaller, thinner, and lighter, and adopting a multilayer structure for printed wiring boards used for surface mounting. . However, it is considered that it will be difficult to further improve the performance of electronic devices and to reduce the size, thickness, and weight of these devices using these methods alone. Therefore, electronic component built-in substrates, which are superior to the conventional printed wiring boards in the following points, are attracting attention.
[0003]
1. Since the electronic components that have been surface-mounted so far are incorporated in the printed wiring board, the degree of integration can be increased.
2. Since the number of electronic components to be surface-mounted is reduced, the degree of freedom in the layout of electronic components on the printed wiring board is improved.
[0004]
3. For the reason that electronic parts can be arranged three-dimensionally, the wiring length between the electronic parts can be shortened to improve electrical characteristics such as high frequency characteristics and noise characteristics.
4). Since the solder connection portion is reduced, connection reliability is improved.
5. Since downsizing is possible and mounting becomes easy, the cost can be reduced.
[0005]
By the way, there is a problem that a substrate with a built-in ceramic electronic component using a ceramic substrate as a substrate has a large shrinkage of the substrate in a high-temperature firing step that is essential for the manufacturing process. That is, it is difficult to control the size and shape of the ceramic electronic component built-in substrate with high accuracy, and it is difficult to realize a high yield. Further, the ceramic base material has a problem that it is inherently easily broken. Further, the ceramic electronic component built-in substrate has a problem that electronic components that can be incorporated are limited to passive elements, and active elements cannot be incorporated.
[0006]
On the other hand, the resin-based electronic component built-in substrate using a resin base material as the base material does not have the above-described problems with respect to the ceramic electronic component-embedded substrate. Therefore, among the electronic component built-in substrates, researches on the resin-based electronic component built-in substrates are being actively conducted.
[0007]
For example, Patent Document 1 below describes a multilayer circuit board including a capacitor in which a dielectric layer is sandwiched between a pair of electrode conductors. Further, this document describes that a dielectric substrate is formed by impregnating a glass woven fabric with a dispersion obtained by dispersing ceramic dielectric powder in a resin.
[0008]
However, the thickness of the dielectric substrate obtained by such a method is limited by the glass woven fabric. Therefore, the thickness of the dielectric substrate obtained by the above method is generally about 50 μm to 60 μm, and is about 20 μm even when the thinnest is formed. Further, in the dielectric substrate obtained by such a method, the volume ratio of the ceramic dielectric powder in the dielectric substrate cannot be increased in consideration of the role of the resin as a binder and the viscosity of the dispersion. That is, the dielectric constant of the dielectric substrate cannot be made comparable to the dielectric constant of the ceramic dielectric powder. For this reason, the technique described in Patent Document 1 cannot form a capacitor having a small size and a large capacity.
[0009]
In Patent Document 2 below, an underprint is formed on a flexible metal substrate using a conductor paste, a dielectric layer is formed thereon using a dielectric paste, and a conductor paste or It describes that a conductor layer is formed using a thermosetting thick film conductor, and a laminate obtained thereby is bonded to an organic layer coated with an adhesive layer. Further, this document describes that the dielectric paste is made of a dispersion of particles such as barium titanate or titanium oxide in a polymer dissolved in a mixture of a plasticizer, a dispersant, and an organic solvent. . Furthermore, this document describes forming a dielectric layer by printing a dielectric paste on a copper foil having an underprint, and drying and firing the paste.
[0010]
However, in the above method using the printing method, the dielectric paste is required to be relatively viscous. Therefore, in this method, it is difficult to form a dielectric layer excellent in film thickness uniformity, to control the thickness of the dielectric layer with high accuracy, and to form a thin dielectric layer. In other words, even the technique described in Patent Document 2 cannot form a capacitor having a small size and a large capacity.
[0011]
[Patent Document 1]
JP-A-5-48271
[0012]
[Patent Document 2]
JP 2001-160672 A
[0013]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an electronic component built-in substrate having a small-sized and large-capacitance capacitor built-in, a semiconductor package using the same, and a method of manufacturing the same. And
[0014]
[Means for Solving the Problems]
According to the first aspect of the present invention, it comprises a resin substrate and a laminated body provided on one main surface thereof, and the laminated body has a first conductor pattern facing the main surface of the resin substrate; An inorganic dielectric layer interposed between the resin substrate and the first conductor pattern, and a second conductor pattern interposed between the resin substrate and the inorganic dielectric layer, at least a part of which An electronic component-embedded substrate is provided which comprises a capacitor, and wherein the inorganic dielectric layer is formed using a sol-gel method.
[0015]
According to the second aspect of the present invention, it comprises a resin substrate and a laminated body provided on one main surface thereof, and the laminated body has a first conductor pattern facing the main surface of the resin substrate; An inorganic dielectric layer interposed between the resin substrate and the first conductor pattern, and a second conductor pattern interposed between the resin substrate and the inorganic dielectric layer, at least a part of which An electronic component-embedded substrate is provided that constitutes a capacitor, and wherein the inorganic dielectric layer contains an alkoxy group as an impurity.
[0016]
According to a third aspect of the present invention, it comprises a resin substrate and a laminate provided on one main surface thereof, the laminate comprising a first conductor pattern facing the main surface of the resin substrate, An inorganic dielectric layer interposed between the resin substrate and the first conductor pattern, and a second conductor pattern interposed between the resin substrate and the inorganic dielectric layer, at least a part of which An electronic component-embedded substrate is provided in which an average grain size of crystal grains constituting a capacitor and constituting the inorganic dielectric layer is in a range of 30 nm to 100 nm.
[0017]
According to a fourth aspect of the present invention, there is provided a semiconductor package comprising: the electronic component substrate according to any one of the first to third aspects; and a semiconductor device mounted on the electronic component built-in substrate. Provided.
[0018]
According to a fifth aspect of the present invention, comprising a resin substrate and a laminate provided on one main surface thereof, the laminate includes a first conductor pattern facing the main surface of the resin substrate, An inorganic dielectric layer interposed between the resin substrate and the first conductor pattern, and a second conductor pattern interposed between the resin substrate and the inorganic dielectric layer, at least a part of which A method of manufacturing a substrate with built-in electronic components constituting a capacitor, the step of forming the inorganic dielectric layer on a first conductor layer by a sol-gel method, and the inorganic dielectric layer and the resin substrate There is provided a method for manufacturing a substrate with built-in electronic components, comprising the step of bonding with the second conductor pattern interposed therebetween.
[0019]
In the first to fifth aspects, the inorganic dielectric layer may be substantially composed of a compound having a perovskite structure.
In the first to fifth aspects, the electronic component built-in substrate may further include an adhesive layer interposed between the resin substrate and the laminate.
[0020]
5th aspect WHEREIN: The process of forming an inorganic dielectric material layer WHEREIN: The 1st conductor layer is the dispersion liquid in which the dielectric material which arises by condensing the hydrolysis product of a metal alkoxide is disperse | distributing as a crystal particle in a dispersion medium. It may be applied to the top, the resulting coating is dried, and the dried coating is fired.
[0021]
Alternatively, the method according to the fifth aspect may further include a step of forming the first conductor pattern by patterning the first conductor layer after the step of bonding the inorganic dielectric layer and the resin substrate. In this case, in the step of forming the inorganic dielectric layer, a solution containing a metal alkoxide and / or a reaction product thereof is applied onto the first conductor layer, the resulting coating film is dried, and the dried coating is applied. The method may include printing a conductive paste on the film and firing the coating film and the conductive paste to form the inorganic dielectric layer and the second conductor pattern, respectively.
[0022]
The method according to the fifth aspect includes a step of forming a second conductor layer on the inorganic dielectric layer by plating before the step of bonding the inorganic dielectric layer and the resin substrate, and the inorganic dielectric layer and the resin substrate. Before the step of bonding together, the step of patterning one of the first and second conductor layers to form the second conductor pattern, and the step of bonding the inorganic dielectric layer and the resin substrate are exposed to the surface A step of patterning the first or second conductor layer to form a first conductor pattern.
[0023]
In the fifth aspect, in the step of forming the inorganic dielectric layer, the back surface of the surface of the first conductor layer on which the inorganic dielectric layer is formed is covered with a coating layer made of a material different from that of the first conductor layer. Also good. In this case, the method may further include a step of removing the coating layer from the first conductor layer after the step of forming the inorganic dielectric layer.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same referential mark is attached | subjected to the structural member which exhibits the same or similar function in each figure, and the overlapping description is abbreviate | omitted.
[0025]
1 to 7 are cross-sectional views schematically showing a method of manufacturing an electronic component built-in substrate according to the first embodiment of the present invention. In the present embodiment, the electronic component built-in substrate is manufactured by the method described below.
[0026]
First, as shown in FIG. 1, an inorganic dielectric layer 14b is formed on the conductor layer 11a by a sol-gel method. A method for forming the inorganic dielectric layer 14b will be described in detail later. Here, a metal foil such as a copper foil is used for the conductor layer 11a.
[0027]
Next, as shown in FIG. 2, a conductor such as a metal layer is formed on the inorganic dielectric layer 14b by using, for example, an electroless plating method, a sputtering method, or a combination of at least one of them and an electroplating method. Layer 12a is formed. Here, as an example, a copper layer is formed as the conductor layer 12a.
[0028]
Subsequently, as shown in FIG. 3, one of the conductor layers 11a and 12a is patterned by using, for example, a photolithography technique and an etching technique. Here, as an example, the conductor layer 12a is patterned to form the conductor pattern 12b.
[0029]
While the laminated body 10 shown in FIG. 3 is formed by the above method, the laminated body 20 shown in FIG. 4 is formed. FIG. 4 shows, as an example, a structure including a resin substrate 21 and a conductor pattern 22 provided thereon. The resin substrate 21 is, for example, a prepreg formed by impregnating a polyimide film or glass cloth with a resin, and the material of the conductor pattern 22 is, for example, copper.
[0030]
Next, as illustrated in FIG. 5, the stacked body 10 and the stacked body 20 are bonded together with an adhesive layer 30 so that the conductor pattern 12 b and the conductor pattern 22 face each other. Subsequently, the insulating oxide layer generated in the process of forming the inorganic dielectric layer 14b is removed from the surface of the conductor layer 11a by using, for example, an etching method.
[0031]
Next, as shown in FIG. 6, through holes for interlayer connection are formed in the laminates 10 and 20 and the adhesive layer 30. Further, the connecting conductor 40 is formed on the side walls of these through holes by using, for example, an electroless plating method. Note that the connecting conductor 40 may be thickened by performing electroplating after the side wall of the through hole is covered with a conductor. In this case, the through hole may be almost completely filled with the connecting conductor 40. Moreover, even if it is not a through-hole, it is sufficient if interlayer connection is possible.
[0032]
Thereafter, as shown in FIG. 7, the conductor layer 11a is patterned by using a photolithography technique and an etching technique. Thereby, the conductor pattern 11b is formed. The electronic component built-in substrate 1 is obtained as described above. In this electronic component built-in substrate 1, the overlapping portion of the conductor pattern 11 b and the conductor pattern 12 b and the inorganic dielectric layer 14 b interposed therebetween constitute a capacitor 50.
[0033]
In the present embodiment, the inorganic dielectric layer 14b is formed by a sol-gel method.
[0034]
According to the sol-gel method, the proportion of the inorganic dielectric in the inorganic dielectric layer 14b can be made extremely high. Therefore, the inorganic dielectric layer 14b having a high dielectric constant can be formed.
[0035]
In general, the viscosity of the coating solution used in the sol-gel method is extremely low. Moreover, this method does not require a glass woven fabric. Therefore, for example, a spin coating method or a spray coating method can be used for applying the coating liquid, and the thin inorganic dielectric layer 14b having excellent film thickness uniformity can be formed. For example, the inorganic dielectric layer 14b having a thickness in the range of 300 nm to 10 μm and excellent film thickness uniformity can be formed.
[0036]
Furthermore, the sol-gel method does not require an expensive vacuum device. Therefore, the electronic component built-in substrate 1 can be manufactured at a relatively low cost.
Therefore, according to this embodiment, it is possible to manufacture an electronic component built-in substrate having a small size and a large-capacity capacitor built-in at a low cost.
[0037]
Specifically, the formation of the inorganic dielectric layer 14b by the sol-gel method can be performed by, for example, the following method.
[0038]
First, one or more metal alkoxides are dissolved in a predetermined solvent to prepare a precursor solution. Here, the metal alkoxide concentration in the precursor solution is, for example, 0.5 mol / L or more.
[0039]
Next, hydrolysis and condensation reaction of the metal alkoxide contained in this precursor solution is caused. Thereby, the previous precursor solution is gelled. The gel produced here has, for example, a single phase containing crystal particles having a crystal structure similar to that of the finally obtained inorganic dielectric layer 14b and typically having a particle size of 50 nm or less. It is a crystalline gel. The crystalline gel can be obtained, for example, by subjecting the above precursor solution to a hydrolysis treatment and an aging treatment at a low temperature as described later.
[0040]
Next, this gel is put into a predetermined solvent, and the crystal particles are dispersed substantially uniformly in the solvent. In this way, a coating liquid for forming the inorganic dielectric layer 14b is obtained.
[0041]
Next, the coating solution is applied onto the conductor layer 11a by using a solution coating method such as a spin coating method or a spray coating method, and the coating film obtained thereby is dried. In addition, since the thickness of the coating film obtained by one application | coating is very thin, this application | coating and drying are repeated several times normally. Then, the inorganic dielectric layer 14b is obtained by baking the coating film.
[0042]
By the way, in a normal sol-gel method, for example, when forming the inorganic dielectric layer 14b mainly composed of a compound having a perovskite structure, that is, a perovskite compound, in order to develop sufficient dielectric properties, 800 Firing at a high temperature of ℃ or higher is necessary. However, firing at such a high temperature may cause problems such as deformation of the conductor layer 11a, which is the base of the inorganic dielectric layer 14b, and reaction at the interface between the base and the inorganic dielectric layer 14b. .
[0043]
On the other hand, in the above-described method, as described above, a coating solution containing crystal particles which are a product of hydrolysis and condensation reaction of metal alkoxide is used. That is, in this method, the reaction of the metal alkoxide is partially advanced before coating. For this reason, the normal sol-gel method requires baking at a high temperature of 800 ° C. or higher, but in this method, baking can be performed at a relatively low temperature, for example, a temperature of 450 ° C. or higher. Therefore, according to this method, the deformation of the conductor layer 11a and the reaction at the interface between the conductor layer 11a and the inorganic dielectric layer 14b hardly occur, and it is denser than the ordinary sol-gel method and The inorganic dielectric layer 14b having excellent composition uniformity can be obtained.
[0044]
The material of the inorganic dielectric layer 14b obtained by the above method is not particularly limited as long as it is a dielectric, but it is advantageous to use a material having a high relative dielectric constant for the inorganic dielectric layer 14b. Such materials include, for example, the general formula: ABO ₃ The perovskite compound represented by these can be mentioned.
[0045]
In the above general formula, “A” is, for example, Cu, Mg, Ca, Sr, Ba, Zn, Cd, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, 1B group, 2A group, 2B group, 3A group, 4B group of the periodic table, such as Ho, Er, Tm, Yb, Lu, Pb, Bi, Fe, Co, and Ni, At least one metal element selected from Group 5B and Group 8 is shown. In the above general formula, “B” is at least selected from Group 4A, Group 4B, and Group 5B of the periodic table, such as Ti, Zr, Hf, Sn, and Sb. One kind of metal element is shown.
[0046]
In this perovskite compound, a part of the metal element A and / or the metal element B can be replaced with another metal element. For example, BaTiO ₃ In this case, a part of Ba is replaced with a metal element A other than Ba, for example, at least one of Sr, Y and La, and (Ba _1-x Sr _x ) TiO ₃ Ya (Ba _1-xyz Sr _x La _y Y _z ) TiO ₃ And so on.
[0047]
The metal alkoxide used in the precursor solution needs to contain the same type of metal as the metal included in the inorganic dielectric layer 14b. However, the type of alkoxy group of the metal alkoxide is not particularly limited.
[0048]
When a perovskite compound is used as the material for the inorganic dielectric layer 14b, a mixture of a plurality of metal alkoxides having different metal element types can be used as the metal alkoxide. Examples of the metal alkoxide that can be used in such a mixture include barium methoxide, barium ethoxide, barium propoxide, barium butoxide, titanium methoxide, titanium ethoxide, titanium propoxide, titanium butoxide, triethoxy yttrium, and triethoxy yttrium. Examples thereof include isopropoxy yttrium, triethoxy lanthanum, triisopropoxy lanthanum, diethoxy strontium, and diisopropoxy strontium.
[0049]
Further, when a perovskite compound is used as the material for the inorganic dielectric layer 14b, a metal alkoxide containing a plurality of types of metal elements different from each other may be used as the metal alkoxide. Examples of such metal alkoxides include barium titanium methoxide, barium titanium ethoxide, barium titanium propoxide, barium titanium butoxide, strontium titanium methoxide, strontium titanium ethoxide, strontium titanium propoxide, and strontium titanium butoxide. Can be used.
[0050]
By appropriately selecting the metal contained in the metal alkoxide or the mixture of metal alkoxides, BeTiO ₃ , MgTiO ₃ , CaTiO ₃ , SrTiO ₃ , BaTiO ₃ , PbTiO ₃ , ZrTiO ₃ , Bi ₂ TiO ₃ , La ₂ TiO ₃ , CeTiO ₃ And ZrTiO ₃ Titanate such as BaSnO ₃ , CaSnO ₃ , SrSnO ₃ MgSnO ₃ , PbSnO ₃ CoSnO ₃ And NiSnO ₃ Stannates such as BaZrO ₃ , CaZrO ₃ , SrZrO ₃ And MgZrO ₃ Zirconate such as MgNbO ₃ , CaNbO ₃ , SrNbO ₃ , BaNbO ₃ And LiNbO ₃ Niobate such as LiTaO ₃ , BaTaO ₃ , SrTaO ₃ , CaTaO ₃ And MgTaO ₃ An inorganic dielectric layer 14b containing various dielectrics such as tantalate can be formed.
[0051]
The solvent used for the precursor solution is not particularly limited as long as it is a solvent that can dissolve the metal alkoxide at a high concentration, for example, a concentration of 0.5 mol / L or more. As the solvent for the precursor solution, for example, an organic solvent such as alcohols such as methanol and ethanol, ketones such as methyl ethyl ketone and acetone may be used alone, or a combination of compatible solvents may be used. A mixed solvent may be used.
[0052]
The hydrolysis of the metal alkoxide contained in the precursor solution is performed, for example, by adding a hydrolyzing agent at a low temperature, typically −30 ° C. to 0 ° C., more typically −20 ° C. to 0 ° C. Can do. As this hydrolyzing agent, for example, an inorganic acid, an organic acid, a hydroxide, and an acid or alkali aqueous solution such as organic amines, water, or the like can be used.
[0053]
The aging treatment after the hydrolysis treatment is performed, for example, at a temperature of 0 ° C. to 60 ° C. for 1 hour to 480 hours, typically at a temperature of 20 ° C. to 60 ° C. for 24 hours to 168 hours. By performing the aging treatment, a crystalline gel containing crystal particles of a substance having a composition corresponding to the composition of the precursor can be obtained. In the crystalline gel obtained under the above conditions, many crystal particles have a particle size of 50 nm or less.
[0054]
By adjusting the conditions of the aging treatment, the ratio of the crystal particles to the gel can be changed. That is, the ratio between the crystal grains and the amorphous phase can be adjusted, and therefore the sinterability (densification and grain growth) of the coating film can be controlled. For example, when the proportion of the crystal particles in the gel is high, there is only a small amount of amorphous phase between the crystal particles, so that the growth of the crystal particles during firing is not large. Therefore, in this case, sintering can be performed at a relatively low temperature and / or in a short time, and a denser inorganic dielectric layer 14b can be obtained. On the other hand, when the proportion of the crystal particles in the gel is low, a large amount of amorphous phase exists between the crystal particles, so that the crystal particles grow greatly during firing. Therefore, energy for growing crystal grains is required. Therefore, in this case, firing is usually performed at a higher temperature and / or longer time in order to sufficiently sinter.
[0055]
As described above, the coating liquid for forming the inorganic dielectric layer 14b is obtained by introducing the above crystalline gel into a predetermined solvent and dispersing the crystal particles substantially uniformly in the solvent. Note that the crystalline gel may be in the form of a slurry or a lump depending on the hydrolysis conditions. In such a case, for example, the produced crystalline gel is put into a solvent used for preparing the coating solution, and the crystal particles are dispersed in the solvent while performing mechanical pulverization or pulverization using ultrasonic waves.
[0056]
The solvent used for the coating solution can be appropriately selected and used according to the type of crystalline gel. As this solvent, for example, organic solvents such as alcohols such as methanol and ethanol, ketones such as methyl ethyl ketone and acetone, water, and the like can be used. In order to facilitate the dispersion of the crystal particles by fine pulverization, this solvent includes, for example, a polymer dispersant such as polyethyleneimine and polyvinylpyrrolidone, and a low molecular system such as sodium dioctylsulfosuccinate. A dispersant or the like can also be added. The type and amount of dispersant used can be appropriately set according to the type of crystalline gel and the type of solvent used in the coating solution.
[0057]
As described above, a spin coat method or a spray coat method can be used to form a coating film on the conductor layer 11a. For the formation of this coating film, other solution coating methods such as dip coating and electrophoretic electrodeposition can also be used. For the formation of this coating film, the above methods may be used alone or in combination.
[0058]
The coating film formed on the conductor layer 11a is subjected to a drying treatment before firing to remove the solvent in the coating film. This drying treatment is performed, for example, by leaving the conductor layer 11a and the coating film formed thereon in an oxygen gas stream at 70 ° C. to 200 ° C. for 0.5 to 5 hours.
[0059]
In forming the inorganic dielectric layer 14b on the conductor layer 11a, the formation and drying of the coating film may be performed only once. Usually, the inorganic dielectric obtained by performing the formation and drying of the coating film only once. The body layer 14b is extremely thin. Therefore, typically, formation and drying of a coating film are performed in multiple times. When forming and drying a coating film several times, the composition of each coating film may be the same or different.
[0060]
As described above, in the previous method, since the crystal particles are generated in the coating solution before forming the coating film, the firing temperature can be made relatively low. In the above method, it is usually sufficient that the firing temperature is 450 ° C. or higher. The firing temperature is usually less than 1200 ° C., typically 800 ° C. or less.
[0061]
The inorganic dielectric layer 14b obtained by the sol-gel method described above has a characteristic that cannot be seen in the inorganic dielectric layer 14b formed by other methods.
For example, since metal alkoxide is used as a raw material, when the hydrolysis and condensation reaction of the metal alkoxide does not proceed completely, the presence of an alkoxy group or a decomposition product thereof may be detected from the inorganic dielectric layer 14b. Therefore, by examining the composition of the inorganic dielectric layer 14b, it may be possible to determine whether or not the inorganic dielectric layer 14b is formed by a sol-gel method.
[0062]
In addition, in the method of generating crystal particles in the coating solution before forming the coating film, the crystal particles do not grow much in the baking process, and many of the crystal particles in the coating solution and coating film before baking are It has a particle size of 50 nm or less. Therefore, in the inorganic dielectric layer 14b obtained by this method, the average particle diameter of the crystal particles is usually within a range of 30 nm to 100 nm, and in many cases, the particle diameter of the crystal particles is distributed within a range of 30 nm to 100 nm. .
[0063]
Thus, the inorganic dielectric layer 14b having a small crystal grain size cannot be obtained by other methods. For example, in the method of forming an inorganic dielectric layer using a mixture of a resin and a dielectric powder, a dielectric powder having an average particle size of about several hundred nm to several hundred μm is used. In addition, in the normal sol-gel method, most of the crystal grain growth occurs in the firing process, and firing is performed at a higher temperature than in the previous method. Therefore, the average grain size of the crystal grains in the obtained inorganic dielectric layer The diameter is about several hundred nm to several hundred μm.
[0064]
Therefore, from the average particle diameter and / or particle size distribution of the crystal particles contained in the inorganic dielectric layer 14b, the inorganic dielectric layer 14b is crystallized in the coating solution before forming the coating film. It is possible to determine whether or not it is formed by the method of generating
[0065]
Next, a second embodiment of the present invention will be described.
The second embodiment is the same as the first embodiment except that the formation method of the conductor pattern 12b is different.
[0066]
8 to 10 are cross-sectional views schematically showing a method for manufacturing an electronic component built-in substrate according to the second embodiment of the present invention. In the present embodiment, the electronic component built-in substrate is manufactured by the method described below.
[0067]
First, as shown in FIG. 8, a coating solution containing a metal alkoxide and / or a reaction product thereof and an organic solvent is applied onto the conductor layer 11a, and the resulting coating film 14a is dried. This application and drying may be performed only once, but is usually repeated a plurality of times. Here, as an example, the coating liquid described in the first embodiment (the coating liquid in which crystal particles are generated) is used as the coating liquid. Further, here, a metal foil that can be used as a base material is used for the conductor layer 11a.
[0068]
Next, as shown in FIG. 9, the conductive paste 12c is printed on the coating film 14a after drying. Here, as an example, a copper paste is used as the conductive paste 12c.
[0069]
Next, the coating film 14a and the conductive paste 12c are baked. Thereby, as shown in FIG. 10, the inorganic dielectric layer 14b and the conductor pattern 12b are obtained.
[0070]
While the laminated body 10 shown in FIG. 10 is formed as described above, for example, the laminated body 20 shown in FIG. 4 is formed. Thereafter, in the first embodiment, the steps described with reference to FIGS. 5 to 7 are sequentially performed. Thus, the electronic component built-in substrate 1 shown in FIG. 7 is obtained.
[0071]
According to this method, the same effect as described in the first embodiment can be obtained. In the electronic component built-in substrate 1 obtained by this method, the inorganic dielectric layer 14 has the characteristics described in the first embodiment.
[0072]
Next, a third embodiment of the present invention will be described.
In the third embodiment, after forming the inorganic dielectric layer 14, the back surface of the conductor layer 11 a on which the inorganic dielectric layer 14 is formed is covered with the coating layer when the inorganic dielectric layer 14 is formed. Except for removing the coating layer from the conductor layer 11a, this is the same as in the first and second embodiments.
[0073]
11 to 14 are cross-sectional views schematically showing a method for manufacturing an electronic component built-in substrate according to the third embodiment of the present invention. In the present embodiment, the electronic component built-in substrate is manufactured by the method described below.
[0074]
First, as shown in FIG. 11, a conductor layer 11 a having one main surface covered with a coating layer 15 is prepared. Next, the inorganic dielectric layer 14b and the conductor pattern 12b are formed on the other main surface of the covering layer 15 by the same method as described in the first or second embodiment.
[0075]
Here, as an example, the covering layer 15 includes a first covering layer 151 made of a material different from that of the conductor layer 11a and a second covering layer 152 made of a material different from that of the first covering layer 151. Here, as an example, a copper layer having a thickness of about 18 μm is used as the conductor layer 11 a and the second coating layer 152, and a nickel layer having a thickness of about 0.5 μm to 1 μm is used as the first coating layer 151. And
[0076]
While the laminated body 10 shown in FIG. 11 is formed as described above, for example, the laminated body 20 shown in FIG. 4 is formed. Thereafter, in the first embodiment, the steps described with reference to FIG. 5 are performed. That is, the laminated body 10 and the laminated body 20 are bonded together via the adhesive layer 30 so that the conductor pattern 12b and the conductor pattern 22 face each other. Thereby, the structure shown in FIG. 12 is obtained.
[0077]
Next, as shown in FIG. 13, the second coating layer 152 is removed from the first coating layer 151 by an etching method. In this etching, an etchant having an etching rate for the second coating layer 152 higher than that for the first coating layer 151 is used.
[0078]
Subsequently, as shown in FIG. 14, the first coating layer 151 is removed from the conductor layer 11a by an etching method. For this etching, an etchant having an etching rate for the first covering layer 151 higher than that for the conductor layer 11a is used.
[0079]
Thereafter, in the first embodiment, the steps described with reference to FIGS. 6 and 7 are sequentially performed. As described above, the electronic component built-in substrate 1 shown in FIG. 7 is obtained.
[0080]
According to this method, the same effect as described in the first embodiment can be obtained. In the electronic component built-in substrate 1 obtained by this method, the inorganic dielectric layer 14 has the characteristics described in the first embodiment.
[0081]
Further, when the surface of the conductor layer 11a is oxidized to form an oxide layer, if the oxide layer is removed by etching, the flatness of the surface of the conductor layer 11a is significantly lowered. On the other hand, according to the above method, the inorganic dielectric layer 14 is formed in a state where the back surface of the conductor layer 11a on which the inorganic dielectric layer 14 is formed is covered with a coating layer. In the step of forming the layer 14, the surface of the conductor layer 11a is not oxidized. In addition, if a material that provides sufficiently high etching selectivity is used for the conductor layer 11a and the first covering layer 151, the surface of the conductor layer 11a deteriorates as the covering layer 15 is removed from the conductor layer 11a. Can also be prevented. Therefore, according to this method, the electronic component built-in substrate 1 excellent in the flatness of the conductor pattern 11b can be obtained.
[0082]
Furthermore, according to this method, the role as a base material for forming the inorganic dielectric layer 14 can be performed not only by the conductor layer 11a but also by the covering layer 15. Therefore, the conductor layer 11a can be made thinner as compared with the methods described in the first and second embodiments. Therefore, according to this method, a thinner electronic component built-in substrate 1 can be obtained.
[0083]
In the first to third embodiments described above, a simple structure is employed for the electronic component built-in substrate 1 in order to simplify the description. However, a more complicated structure may be employed.
[0084]
FIG. 15 is a cross-sectional view schematically showing an electronic component built-in substrate according to the fourth embodiment of the present invention.
[0085]
In the electronic component built-in substrate 1 shown in FIG. 15, the overlapping portion of the conductor patterns 11b, 12b, and 13b and the inorganic dielectric layer 14b interposed therebetween constitute the capacitor 50. In the electronic component built-in substrate 1, the conductor pattern 22 is provided above and below the capacitor 50. Thus, the electronic component built-in substrate 1 can be a multilayer substrate.
[0086]
Further, the electronic component built-in substrate 1 can be further modified. For example, the electronic component built-in substrate 1 includes only a capacitor as an electronic component, but may further include other electronic components such as a resistor and an inductor. The electronic component built-in substrate 1 can also incorporate a semiconductor device.
[0087]
The electronic component built-in substrate 1 according to the first to fourth embodiments can be used as, for example, a printed wiring board or an interposer used for surface mounting of a semiconductor chip or a semiconductor package.
[0088]
FIG. 16 is a cross-sectional view schematically showing a semiconductor package using the electronic component built-in substrate according to the first to fourth embodiments as an interposer. FIG. 17 is a cross-sectional view schematically showing a semiconductor module using the electronic component built-in substrate according to the first to fourth embodiments as a printed wiring board.
[0089]
In the semiconductor package 5 shown in FIG. 16, the electronic component built-in substrate 1 according to any of the first to fourth embodiments is used as an interposer, and the semiconductor chip 2 is flip-chip bonded. In the figure, reference numeral 3 indicates a metal bump, and reference numeral 4 indicates a resin layer such as underfill.
In the semiconductor module 7 shown in FIG. 17, the electronic component built-in substrate 1 according to any of the first to fourth embodiments is used as a printed wiring board, and the semiconductor chip 2 and the semiconductor package 5 are mounted on the surface. Yes.
[0090]
Thus, the electronic component built-in substrate 1 according to the first to fourth embodiments can be used for various applications.
[0091]
【Example】
Examples of the present invention will be described below.
(Example 1)
In this example, the electronic component built-in substrate 1 shown in FIG. 7 was manufactured by the method described below.
[0092]
First, at room temperature, Ba (OC ₂ H ₅ ) ₂ , Sr (OC ₂ H ₅ ) ₂ , And Ti (O-iC ₃ H ₇ ) ₄ Was prepared in a molar ratio of 1: 1: 2. Here, as the solvent, a mixture of methanol and 2-methoxyethanol in a volume ratio of 6: 4 was used, and the alkoxide concentration in the solution was 1.0 mol / L.
[0093]
Next, this precursor solution was hydrolyzed with water vapor at 0 ° C. and then aged at 50 ° C. for 48 hours. As a result, a single-phase crystalline gel containing crystal grains of barium strontium titanate having a particle size of 50 nm or less was obtained.
[0094]
Further, this crystalline gel was put into 2-methoxyethanol and uniformly dispersed while being finely pulverized using ultrasonic waves. As described above, a coating solution for forming a thin film was prepared.
[0095]
With respect to this coating solution, the particle size distribution of particles dispersed in the coating solution was measured by a light scattering method. As a result, it was distributed within a range of about 8 nm to 40 nm, and it was confirmed that coarse particles were not present.
[0096]
Next, the above coating solution was spin-coated on the copper foil 11a, and the obtained coating film was dried in an oxygen stream at 150 ° C. for 0.5 hours. This application and drying were repeated a total of 5 times, and then fired in the atmosphere at a temperature of 450 ° C. for 1 hour. Thus, as shown in FIG. 1, a 0.5 μm-thick barium strontium titanate thin film was formed as the inorganic dielectric layer 14b.
[0097]
The inorganic dielectric layer 14b was observed using a transmission electron microscope. As a result, it was confirmed that the inorganic dielectric layer 14b was mainly composed of crystal particles, and the particle diameters of these particles were distributed within the range of 30 nm to 100 nm.
[0098]
Next, a thin copper layer was formed on the inorganic dielectric layer 14b by electroless plating. Subsequently, copper was further deposited on the copper layer by electroplating. Thus, the copper layer 12a shown in FIG. 2 was obtained.
[0099]
Next, the copper pattern 12b shown in FIG. 3 was formed by patterning the copper layer 12a using a photolithography technique and an etching technique. The copper pattern 12b is a pattern corresponding to one electrode of the capacitor 10 and a wiring disposed in the same plane as the electrode.
[0100]
3 is formed by the above-described method, while a copper layer provided on one main surface of a prepreg 21 formed by impregnating a glass cloth with an epoxy resin is patterned to form a copper pattern 22 as a wiring pattern. did. Thus, the laminated body 20 shown in FIG. 4 was obtained.
[0101]
Then, as shown in FIG. 5, the laminated body 10 and the laminated body 20 were bonded together through the adhesive bond layer 30 so that those copper patterns 12b and 22 might face each other.
[0102]
Next, a through hole was formed in the structure of FIG. 5 using a laser. Subsequently, as shown in FIG. 6, the side wall of the through hole was covered with a copper layer 40 by an electroless plating method and an electroplating method. At this time, the outer surface of the laminate 20 was covered with a dry film photoresist (hereinafter referred to as a dry film).
[0103]
Subsequently, the copper pattern 11b shown in FIG. 7 was obtained by patterning the copper layer 11a using the photolithography technique and the etching technique. The copper pattern 11b is a pattern corresponding to the other electrode of the capacitor 10 and wirings and terminals arranged in the same plane.
[0104]
By the above method, the electronic element built-in substrate 1 including the capacitor 50 having a size of 0.25 mm × 0.25 mm was obtained.
[0105]
The capacitance of the capacitor 50 was examined for the electronic element built-in substrate 1. As a result, the capacitance of the capacitor 50 was about 55 pF on average, and it was confirmed that there was very little variation.
[0106]
(Example 2)
A substrate with a built-in electronic element 1 shown in FIG. 7 was produced by the same method as described in Example 1 except that the following coating solution was used.
[0107]
That is, first, Ba (OC ₂ H ₅ ) ₂ And Ti (O-iC ₃ H ₇ ) ₄ Was prepared in a molar ratio of 1: 1. Here, as the solvent, a mixture of methanol and 2-methoxyethanol in a volume ratio of 6: 4 was used, and the alkoxide concentration in the solution was 1.0 mol / L.
[0108]
Next, this precursor solution was hydrolyzed with water vapor at 0 ° C. and then aged at 25 ° C. for 24 hours. As a result, a single-phase crystalline gel containing crystal particles of barium titanate having a particle size of 50 nm or less was obtained.
[0109]
Further, this crystalline gel was put into 2-methoxyethanol and uniformly dispersed while being finely pulverized using ultrasonic waves. As described above, a coating solution for forming a thin film was prepared.
[0110]
With respect to this coating solution, the particle size distribution of particles dispersed in the coating solution was measured by a light scattering method. As a result, it was distributed within a range of about 8 nm to 40 nm, and it was confirmed that coarse particles were not present.
[0111]
Thereafter, the same steps as described in Example 1 were sequentially performed except that this coating solution was used. In this way, the electronic element built-in substrate 1 provided with a 0.7 μm-thick barium titanate thin film as the inorganic dielectric layer 14b was completed.
[0112]
In this example as well, the inorganic dielectric layer 14b was observed using a transmission electron microscope. As a result, it was confirmed that the inorganic dielectric layer 14b was mainly composed of crystal particles, and the particle diameters of these particles were distributed within the range of 30 nm to 100 nm.
[0113]
Further, the capacitance of the capacitor 50 was examined for the electronic element built-in substrate 1. As a result, the capacitance of the capacitor 50 was about 30 pF on average, and it was confirmed that there was very little variation.
[0114]
【The invention's effect】
As described above, according to the present invention, an electronic component built-in substrate incorporating a capacitor with a small size and a large capacity, a semiconductor package using the substrate, and a manufacturing method thereof are provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing a method for manufacturing an electronic component built-in substrate according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view schematically showing the method for manufacturing the electronic component built-in substrate according to the first embodiment of the present invention.
FIG. 3 is a cross-sectional view schematically showing the method for manufacturing the electronic component built-in substrate according to the first embodiment of the present invention.
FIG. 4 is a cross-sectional view schematically showing the method for manufacturing the electronic component built-in substrate according to the first embodiment of the present invention.
FIG. 5 is a cross-sectional view schematically showing the method for manufacturing the electronic component built-in substrate according to the first embodiment of the present invention.
FIG. 6 is a cross-sectional view schematically showing the method for manufacturing the electronic component built-in substrate according to the first embodiment of the present invention.
FIG. 7 is a cross-sectional view schematically showing the method for manufacturing the electronic component built-in substrate according to the first embodiment of the present invention.
FIG. 8 is a cross-sectional view schematically showing the method for manufacturing the electronic component built-in substrate according to the second embodiment of the present invention.
FIG. 9 is a cross-sectional view schematically showing a method for manufacturing an electronic component built-in substrate according to a second embodiment of the present invention.
FIG. 10 is a cross-sectional view schematically showing the method for manufacturing the electronic component built-in substrate according to the second embodiment of the present invention.
FIG. 11 is a cross-sectional view schematically showing a method for manufacturing the electronic component built-in substrate according to the third embodiment of the present invention.
FIG. 12 is a cross-sectional view schematically showing the method for manufacturing the electronic component built-in substrate according to the third embodiment of the present invention.
FIG. 13 is a cross-sectional view schematically showing the method for manufacturing the electronic component built-in substrate according to the third embodiment of the present invention.
FIG. 14 is a cross-sectional view schematically showing the method for manufacturing the electronic component built-in substrate according to the third embodiment of the present invention.
FIG. 15 is a sectional view schematically showing an electronic component built-in substrate according to a fourth embodiment of the invention.
FIG. 16 is a cross-sectional view schematically showing a semiconductor package using the electronic component built-in substrate according to the first to fourth embodiments as an interposer.
FIG. 17 is a cross-sectional view schematically showing a semiconductor module using the electronic component built-in substrate according to the first to fourth embodiments as a printed wiring board;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Electronic component built-in board, 2 ... Semiconductor chip, 3 ... Metal bump, 4 ... Resin layer, 5 ... Semiconductor package, 7 ... Semiconductor module, 10 ... Laminated body, 11a ... Conductor layer, 11b ... Conductor pattern, 12a ... Conductor Layer, 12b ... conductor pattern, 12c ... conductive paste, 13b ... conductor pattern, coating film 14a ..., 14b ... inorganic dielectric layer, 15 ... coating layer, 20 ... laminate, 21 ... resin substrate, 22 ... conductor pattern, 30 ... adhesive layer, 40 ... connecting conductor, 50 ... capacitor, 151 ... first coating layer, 152 ... second coating layer 152.

Claims (12)

Comprising a resin substrate and a laminate provided on one main surface thereof,
The laminate includes a first conductor pattern facing the main surface of the resin substrate, an inorganic dielectric layer interposed between the resin substrate and the first conductor pattern, the resin substrate, and the inorganic dielectric. And a second conductor pattern interposed between the layers, at least a part of which constitutes a capacitor,
The substrate with a built-in electronic component, wherein the inorganic dielectric layer is formed using a sol-gel method. The inorganic dielectric layer forms a coating film using a dispersion in which a dielectric formed by condensation of metal alkoxide hydrolysis products is dispersed in a dispersion medium as crystal particles, and the coating film is dried. The electronic component built-in substrate according to claim 1, wherein the electronic component-embedded substrate is formed by firing. Comprising a resin substrate and a laminate provided on one main surface thereof,
The laminate includes a first conductor pattern facing the main surface of the resin substrate, an inorganic dielectric layer interposed between the resin substrate and the first conductor pattern, the resin substrate, and the inorganic dielectric. And a second conductor pattern interposed between the layers, at least a part of which constitutes a capacitor,
The substrate with a built-in electronic component, wherein the inorganic dielectric layer contains an alkoxy group as an impurity. Comprising a resin substrate and a laminate provided on one main surface thereof,
The laminate includes a first conductor pattern facing the main surface of the resin substrate, an inorganic dielectric layer interposed between the resin substrate and the first conductor pattern, the resin substrate, and the inorganic dielectric. And a second conductor pattern interposed between the layers, at least a part of which constitutes a capacitor,
An electronic component-embedded substrate, wherein an average grain size of crystal grains constituting the inorganic dielectric layer is in a range of 30 nm to 100 nm. 5. The electronic component built-in substrate according to claim 1, wherein the inorganic dielectric layer is substantially made of a compound having a perovskite structure. The electronic component built-in substrate according to any one of claims 1 to 5, further comprising an adhesive layer interposed between the resin substrate and the laminate. A semiconductor package comprising: the electronic component substrate according to claim 1; and a semiconductor device mounted on the electronic component built-in substrate. A resin substrate and a laminate provided on one main surface of the resin substrate, wherein the laminate includes a first conductor pattern facing the main surface of the resin substrate, the resin substrate, and the first conductor pattern. And a second conductive pattern interposed between the resin substrate and the inorganic dielectric layer, at least a part of which is a capacitor built-in electronic component built-in substrate A method,
Forming the inorganic dielectric layer on the first conductor layer by a sol-gel method;
And a step of bonding the inorganic dielectric layer and the resin substrate with the second conductor pattern interposed therebetween. The step of forming the inorganic dielectric layer is performed by applying a dispersion liquid in which a dielectric produced by condensation of a hydrolysis product of a metal alkoxide is dispersed in a dispersion medium as crystal particles on the first conductor layer. The method for producing an electronic component built-in substrate according to claim 8, comprising drying the coating film obtained thereby and firing the coating film after drying. After the step of bonding the inorganic dielectric layer and the resin substrate, further comprising the step of patterning the first conductor layer to form the first conductor pattern;
In the step of forming the inorganic dielectric layer, a solution containing a metal alkoxide and / or a reaction product thereof is applied onto the first conductor layer, a coating film obtained thereby is dried, and the coating after drying is applied. The method includes printing a conductive paste on a film and firing the coating film and the conductive paste to form the inorganic dielectric layer and the second conductor pattern, respectively. 9. A method for producing an electronic component built-in substrate according to 8. Forming a second conductor layer on the inorganic dielectric layer by plating before the step of bonding the inorganic dielectric layer and the resin substrate; and
Patterning any one of the first and second conductor layers to form the second conductor pattern before the step of bonding the inorganic dielectric layer and the resin substrate; and
And further comprising a step of patterning the first or second conductor layer exposed on the surface after the step of bonding the inorganic dielectric layer and the resin substrate to form the first conductor pattern. The manufacturing method of the electronic component built-in substrate according to claim 8. In the step of forming the inorganic dielectric layer, the back surface of the surface of the first conductor layer on which the inorganic dielectric layer is formed is covered with a coating layer made of a material different from the first conductor layer,
9. The method of manufacturing an electronic component built-in substrate according to claim 8, further comprising a step of removing the covering layer from the first conductor layer after the step of forming the inorganic dielectric layer.

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