JP2001313467A - Wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board which is free from cracking or breaking in resin or a wiring board body and ensures electric continuity of electronic components and inner wiring layers or the like surely and stably, in a wiring board wherein the electronic components are included in the wiring board body via the resin. SOLUTION: This wiring board is provided with an insulating wiring board body (core board) 2 having a surface 3 and a back 4, through holes 6 formed in the wiring board body 2, and chip capacitors (electronic components) 12 which are included in the through holes 6 and fixed via resin 11. Thermal expansion coefficients α1, α2, α3 of the wiring board body 2, the resin 11 and the capacitor 12 are related by a formula 1; α3<α1<=α2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board having electronic components built in a wiring board main body, and a wiring board having a semiconductor element such as an IC chip mounted above the surface of the wiring board.

[0002]

2. Description of the Related Art In order to cope with recent miniaturization of wiring boards and densification of wiring in the wiring boards, not only electronic parts such as IC chips are mounted on a first main surface of the wiring board, but also cores are mounted. 2. Description of the Related Art There has been proposed a wiring board in which electronic components are embedded inside a board. For example, in a wiring board 50 shown in FIG. 5A, a chip capacitor 53 is inserted into a through hole 52 formed in an insulating substrate 51, and electrodes 54, 54 at both ends thereof are provided.
Are connected to the lands 57 formed between the insulating substrate 51 and the adjacent insulating layer 56 via solder 58. By filling the resin 59 in the through-hole 52, the capacitor 53 is fixedly mounted. An internal electrode 55 is provided inside the capacitor 53.

In a wiring board 60 shown in FIG. 5B, one opening of a through hole 62 formed in an insulating substrate 61 is closed in advance with an adhesive temporary fixing film (not shown). In a state where the chip capacitor 63 having the internal electrode 65 is adhered, the resin 69 is filled in the through hole 62 and solidified, and then the temporary fixing film is removed. The wiring board 60 includes, as shown in FIG.
The electrodes 64, 64 located at both ends of the substrate are connected to lands 67, 67 provided in advance between the insulating substrate 61 and the insulating layer 66 adjacent thereto via solder 68.

[0004]

However, in the wiring boards 50 and 60 described above, the insulating boards 51 and 61 and the through holes 5 are provided.
Between the resin 59 and 69 to be filled in the second and the second 62, and
In at least one of between the resins 59 and 69 and the capacitors (electronic parts) 53 and 63 embedded therein,
During the heating in the manufacturing process, cracks may occur in the insulating substrates 51 and 61 and the resins 59 and 69 near the boundary due to the difference in the coefficient of thermal expansion. For this reason, since the solders 58 and 68 are broken or separated, the electronic components 53 and 63 and the wiring boards 50 and 60 are separated.
There has been a problem that the conduction with the internal wiring layer becomes unstable or breaks. The present invention solves the problems in the conventional technology described above, and in a wiring board in which electronic components are embedded in a wiring board body via a resin, the resin or the wiring board body is not broken or broken, It is an object of the present invention to provide a wiring board capable of reliably and stably providing conduction between a component and an internal wiring layer.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has been made by focusing on the relationship between the thermal expansion coefficients of a wiring board main body, a resin, and embedded electronic components. is there. That is, the first wiring board of the present invention (Claim 1) includes an insulating wiring board body having front and back surfaces, a through hole or a recess provided in the wiring board body, and An electronic component that is built-in and fixed through a resin, and has a coefficient of thermal expansion α1, α2, α3 of the wiring board body, the resin, and the electronic component.
(That is, the thermal expansion coefficient of the wiring board body is α1, the thermal expansion coefficient of the resin is α2, and the thermal expansion coefficient of the electronic component is α3).
Is characterized by the following relationship.

[0006]

## EQU4 ## α3 <α1 ≦ α2

According to this, the thermal expansion coefficient α of the wiring board body is
1 is larger than the coefficient of thermal expansion α3 of the electronic component and is equal to or smaller than the coefficient of thermal expansion α2 of the resin in which the electronic component is embedded. Therefore, even when the electronic component expands when the melted resin is solidified or heated at a separate position, the wiring board body and the resin further expand significantly. As a result, the size of the through hole or the concave portion of the wiring board main body or the resin itself surrounding the electronic component increases. Accordingly, it is possible to prevent the resin or the wiring board body from being broken or damaged, so that it is possible to stably and reliably establish conduction between the electronic component and the internal wiring layer. In this specification, the coefficient of thermal expansion refers to the vertical and horizontal directions of the object (X-Y, a direction perpendicular to the thickness direction of the wiring board).
The coefficient of thermal expansion in the direction.

A second wiring board according to the present invention comprises an insulating wiring board main body having front and rear surfaces, a through hole or a recess provided in the wiring board main body, and an inside of the through hole or the recess. An electronic component built in and fixed through a resin, and a semiconductor element mounted above the surface of the wiring board main body and electrically connected to the electronic component, and the wiring board main body, the resin, and the electronic component And the thermal expansion coefficients α1, α2, α3, α4 of the semiconductor element (that is, the thermal expansion coefficient of the wiring board body: α1, the thermal expansion coefficient of the resin: α2, the thermal expansion coefficient of the electronic component: α3, the heat of the semiconductor element) Expansion coefficient: α4)
Is in the relationship of Expression 5.

[0009]

[Equation 5] α4 ≦ α3 <α1 ≦ α2

[0010] According to this, in addition to the relationship of the above equation 4,
The coefficient of thermal expansion α4 of the semiconductor element is equal to or less than the coefficient of thermal expansion α3 of the built-in electronic component. For this reason, for example, when soldering when mounting the semiconductor element on the first main surface of the wiring board, even if the semiconductor element thermally expands, it becomes equal to or less than the electronic component, and the wiring board body and the electronic component are embedded. It does not affect the resin that is used. Therefore, the semiconductor element and the electronic component mounted on the first main surface or the like can be reliably and stably conducted directly or via the internal wiring layer, and
It is also possible to efficiently manufacture such a wiring board.

According to a third aspect of the present invention, there is provided an insulating wiring board body having front and rear surfaces, a through hole or a recess provided in the wiring board body, and a through hole or a recess formed in the through hole or the recess. An electronic component embedded in and fixed through a resin, and an insulating layer formed on at least one of the front surface and the back surface of the wiring substrate main body, and the wiring substrate main body, the resin, the electronic component, And the thermal expansion coefficients α1, α2, α3, α5 of the insulating layer (that is, the thermal expansion coefficient of the wiring board body: α1, the thermal expansion coefficient of the resin: α2, the thermal expansion coefficient of the electronic component: α3, the thermal expansion of the insulating layer) Ratio: α5) in the relationship of Expression 6.

[0012]

[Equation 6] α3 <α1 ≦ α2 ≦ α5

According to this, in addition to the relation of the above-mentioned formula 4,
The coefficient of thermal expansion α5 of the insulating layer has the same or higher relationship as the coefficient of thermal expansion α2 of the resin. For this reason, when the resin is solidified or heated at a separate position, even if the electronic component, the wiring board body, and the resin expand, the insulating layer expands more than these, so that the resin or the like Can absorb swelling. Accordingly, it is possible to prevent the resin or the wiring board main body from being broken or damaged, so that it is possible to stably and reliably establish electrical conduction between the electronic component and the wiring layer between the insulating layers.

Further, the coefficient of thermal expansion α2 of the resin is 40 p
A wiring board having a lower than pm / ° C. is also included in the present invention.
According to this, it is possible to prevent the resin or the wiring board main body from being cracked or damaged, and to more reliably prevent the expansion of the semiconductor element from affecting the wiring board main body. The coefficient of thermal expansion α2 is 35 ppm / ° C. or less (preferably 30 ppm / ° C. or less, more preferably 25 pp / ° C. or less).
m / ° C. or lower, more preferably 20 ppm / ° C. or lower, provided that the lower limit is 10 ppm / ° C. or higher). It should be noted that any of the above-mentioned wiring board bodies includes an insulating substrate having internal wiring and a multilayer substrate such as a substrate in which a plurality of insulating plates and wiring are laminated. Further, these wiring board bodies may be wiring board bodies containing glass cloth or glass filler.

[0015]

Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows one embodiment of the present invention.
2 shows a cross section of a main part in a wiring board 1 of the embodiment. The wiring board 1 includes a wiring board body (hereinafter, referred to as a core board) 2 and a plurality of insulating layers 22, 23, 28,
9, 34, 35 and wiring layers 20, 21, 26, 27, 3
2, 33. The wiring layers 20, 26, 32 and the insulating layers 22, 28, 34 above the surface 3 of the core substrate 2
The build-up layer BU1 is formed, and the wiring layers 21, 27, 33 and the insulating layers 23, 29, 35 below the back surface 4 form the build-up layer BU2. The core substrate 2 is made of a glass cloth-epoxy resin composite material, and is an insulating plate material having a rectangular shape in plan view. Having.
In the through hole 6, a box-shaped electronic component unit 10 is provided.
Are fixed and embedded via a resin 11 containing an epoxy resin as a main component. In this embodiment, a resin having a thermal expansion coefficient α2 of 32 ppm / ° C. is used as the resin 11.

As shown in FIG. 2, the electronic component unit 10 includes eight chip capacitors (electronic components) having the same shape.
12 is integrally fixed in advance by a mold resin 18 made of an epoxy resin. The mold resin 18 has the same thermal expansion coefficient α2 as that of the resin 11 at 32 ppm /
Use a resin at ° C. On the upper surface of each chip capacitor 12, a pair of electrodes
Are formed on the bottom surface of each chip capacitor 12 at the same position. The upper ends of the electrodes 14 and 16 protrude from the front and back surfaces of the mold resin 18 by about several tens μm. Each capacitor 12
For example, a ceramic capacitor in which a dielectric layer mainly containing barium titanate and an electrode layer mainly containing Ni are alternately laminated is used.

As shown in FIG. 1, through holes 6 in core substrate 2 are provided.
Through holes 7 are drilled on the left and right sides of the hole, and a cylindrical through-hole conductor 8 and a filling resin 9 are formed therein. Front and back surfaces 3 and 4 of core substrate 2 and resin 1
The copper wiring layer 2 having a predetermined pattern is formed on the front and back surfaces of the substrate 1 by a known build-up process (subtractive method, fully additive method, semi-additive method, etc.).
0 and 21 are formed by Cu plating. Wiring layer 2
0 and 21 are above the electrodes 14 and 16 of the electronic component 12.
It is connected to the lower end. On the wiring layers 20 and 21, insulating layers 22 and 23 containing epoxy resin as a main component and containing an inorganic filler such as silica and wiring layers 26 and 2 thereover are provided.
7 are formed, and filled via conductors 24 and 25 connecting between the upper and lower wiring layers 20 and 26 and between the wiring layers 21 and 27 are formed.
Are formed through the insulating layers 22 and 23 by copper plating. The formation of the via hole before the formation of the via conductor 24 and the like is performed by a photolithography technique or laser (YAG, CO ₂ , excimer, etc.) irradiation. Further, the electrodes 14 and 16 of each of the capacitors 12 are connected to the wiring layer 2 which also serves as a conversion layer that is continuous in the left-right direction immediately above.
6, 27 are connected to each other. Therefore, the eight capacitors 12 are connected in parallel to form a combined capacitor having a large capacitance.

Similarly, on the wiring layers 26 and 27, insulating layers 28 and 29, wiring layers 32 and 33, and filled via conductors 30 and 31 are formed. Furthermore, a solder resist layer (insulating layer) formed on the insulating layer 28 and the wiring layer 32
Reference numeral 34 denotes a first main surface 3 located on the wiring layer 32 and having an upper end.
A plurality of flip chip bumps 36 made of solder projecting higher than 4a penetrate. Connection terminals 39 on the bottom surface of an IC chip (semiconductor element) 38 mounted on the first main surface 34a are individually connected to each bump 36, and an underfill material 39a mainly composed of epoxy resin is Is filled to a thickness of about 60 μm. On the other hand, a solder resist (insulating layer) layer 35 is formed below the insulating layer 29 and the wiring layer 33, and a plurality of openings 35 b opened toward the second main surface 35 a are provided in the wiring layer 33. The wiring 37 is exposed, its surface is coated with thin Ni and Au plating, and a connection terminal for connecting to a motherboard (not shown) is formed. A pin (Kovar, Fe-42 wt% Ni alloy, copper, etc.) may be soldered to the wiring 37 serving as such a connection terminal.

Here, main steps of the method of manufacturing the wiring board 1 will be described with reference to FIG. FIG. 3 (A) is a plan view of a core substrate 2 containing a glass cloth having a square shape, a side of 31 mm and a thickness of 0.8 mm in a plan view.
A state in which the electronic component unit 10 having a square of 9 mm on a side and a thickness of 0.75 mm is inserted into the through-hole 6 having a square of 2 mm is shown. As shown in FIG. 3A, the opening of the through hole 6 on the back surface 4 side is previously closed by the tape 5 with the adhesive surface 5a facing upward. The electronic component unit 10 inserted into the through hole 6 is positioned by bonding a plurality of electrodes 16 of each chip capacitor 12 projecting to the back surface side to the adhesive surface 5 a of the tape 5.

In a state where the unit 10 is positioned, a melted resin 11 containing an epoxy resin as a main component is injected into the through hole 6 from the front surface 3 side, and then cured and solidified. As a result, as shown in FIG. 3B, the electronic component unit 10 is fixed to the resin 11 solidified in the through hole 6 and is built therein. The mold resin 18 of the electronic component unit 10 is integrated with the resin 11 after the curing process, and becomes the resin 11 that fixes and incorporates the electronic components 12 and 12.
(That is, since the mold resin 18 and the resin 11 have the same coefficient of thermal expansion, they are substantially the same.) Further, when the tape 5 is peeled off, the lower end surfaces of the electrodes 16 are exposed on the flat back surface 11b of the resin 11 following the tape 5. Next, the raised surface 11a of the resin 11 shown in FIG.
Is flattened by, for example, buffing. As a result,
As shown in FIG. 3C, the upper end surfaces of the plurality of electrodes 14 are exposed on a new surface 11c of the resin 11.

Thereafter, the build-up layers BU1, BU2 composed of the insulating layers 22, 23, etc. and the wiring layers 20, 21, 26, 27, etc., and the via conductors 2 are formed by the above-described method.
4, 25, etc., and the bumps 36 and wirings 37 for connection terminals are formed. It is more desirable that the rear surface 11b of the resin 11 be leveled in the same manner as described above. In the above-described manufacturing method, the unit 10 in which a plurality of electronic components 12 are integrated in advance is used. However, after each electronic component 12 is individually embedded in the through hole 6 using a chip mounter or the like, the resin 11 And curing treatment can be performed. By the way, the thermal expansion coefficients α1, α2, α3 of the core substrate 2, the resin 11, and the chip capacitor 12, which is an electronic component, are given by the following equations.
Are set in advance so that

[0022]

Equation 3 α3 <α1 ≦ α2

In the present embodiment, α1: 15 ppm / ° C.,
α2: 32 ppm / ° C., α3: 10 ppm / ° C.
Thereby, the heating during the curing process of the resin 11 and the first
When the bumps 36 are heated when the IC chip 38 is mounted on the main surface 34a, even if each capacitor 12 expands, the core substrate 2 and the resin 11 further expand more, and the through-hole 6 of the core substrate 2 Resin 1 surrounding capacitor 12
1 itself becomes large. Accordingly, it is possible to prevent the resin 11 and the core substrate 2 from being broken or damaged, so that it is possible to reliably ensure the conduction between the capacitors 12 and the internal wiring layers 20 and 21 in a stable state. The coefficient of thermal expansion of the mold resin 18 used in the electronic component unit 10 is substantially the same as the coefficient of thermal expansion α2 of the resin 11. Further, when the coefficient of thermal expansion α4 of the IC chip (semiconductor element) 38 is further added to Expression 7, the relationship of Expression 8 is obtained.

[0024]

[Equation 8] α4 ≦ α3 <α1 ≦ α2

In the present embodiment, α4: 4 ppm / ° C. Therefore, for example, the IC chip 3 is placed on the first main surface 34a.
When the IC chip 38 is thermally expanded during the heating of the bumps 36 when mounting the IC chip 8, the coefficient of thermal expansion α4 of each
Since it is equal to or less than (electronic component) 12, it does not affect the core substrate 2 or the resin 11 in which the capacitor 12 is embedded. Therefore, the mounted IC chip 38 and each capacitor 1
2 can be reliably and stably conducted through the wiring layer 20 or the like. Further, with respect to Equation 7, the insulating layers 22, 23, 2 forming the buildup layers BU1, BU2
When the coefficient of thermal expansion α5 such as 8, 29 is added, the relationship of Expression 9 is obtained.

[0026]

## EQU9 ## α3 <α1 ≦ α2 ≦ α5

In this embodiment, α5 is set to 60 ppm / ° C. Therefore, in addition to the relationship of the above equation 7, the insulating layer 2
The coefficient of thermal expansion α5, such as 2, 23, has a relationship equal to or greater than the coefficient of thermal expansion α2 of the resin. As a result, when the resin 11 is solidified or heated at a separate position, each of the capacitors (electronic components) 12, the wiring board body 2, and the resin 11
When the insulating layer 22 and 23 expand, the expansion of the resin 11 and the like can be absorbed. Therefore, since the resin 11 and the wiring board main body 2 can be prevented from being broken or broken, conduction between each capacitor 12 and the wiring layers 26, 27 between the insulating layers 22, 23, 28, 29 and the like is stabilized. Can be taken reliably.

According to the wiring board 1 as described above, the electrodes 14 and the electrodes 14 of the respective chip capacitors 12 in the electronic component unit 10 built in the through holes 6 of the core board (wiring board main body) 2 via the resin 11. The connection between the wiring layer 16 and the wiring layers 20 and 21 is hardly broken, and the conduction is stabilized. still,
The electrodes 14 and 16 of each capacitor 12 and the wiring layers 20 and 21 connected thereto are preferably made of the same material such as the above-mentioned Cu and having a higher melting point than solder. Thus, disconnection can be prevented even when the solder bumps 36 are heated when the IC chip 38 is mounted.

For this reason, each capacitor 12 and the first main surface 3
Stable continuity can also be obtained with relatively short wiring between the IC chip 38 mounted on 4a. Also, the wiring (connection terminal) on the electrode 16 of each capacitor 12 and the second main surface 35 side.
Stable conduction can be obtained with relatively short wiring between
In addition, continuity with the motherboard on which the wiring board 1 itself is mounted is also ensured. Accordingly, in the wiring board 1 having a small size and high wiring density, it is possible to stably utilize the capacitors 12 as the electronic components incorporated in the core board 2 and to make them excellent in durability. it can. The wiring layers 20 and 21 are electrically connected to each other via the through-hole conductor 8 separately from the capacitors 12. The via conductors 24, 25, 30, 31 are preferably the filled vias shown in FIG. 1 and stacked vias which are linearly stacked in the thickness direction. Thereby, each capacitor 12 and the IC chip 38 mounted on the first main surface 34a can be connected with the shortest distance, so that the electrical characteristics are improved and the distance between each capacitor 12 and the motherboard is also short. Can be connected.

[0030]

Now, specific examples of the wiring board of the present invention will be described together with comparative examples. Core substrate 2 of the same size as above
And a plurality of electronic component units 10 are fixed in the through holes 6 by using resins 11 having different thermal expansion coefficients α2 under the same conditions as shown in FIG. did. Among them, the coefficient of thermal expansion α2 of the resin 11 is 1
Those having 5 ppm / ° C and 32 ppm / ° C were referred to as Examples 1 and 2, and those having a thermal expansion coefficient α2 of 45 ppm / ° C were referred to as Comparative Example 1. Examples 1 and 2 and a part of Comparative Example 1 are shown in FIG.
And the first main surface 3
4a through an underfill material 39a having a coefficient of thermal expansion of 30 ppm / ° C. or less, the I having a coefficient of thermal expansion α4 of 4 ppm / ° C.
The C chip 38 was mounted. Of these, those using the core substrate 2 of Examples 1 and 2 were used in Examples 3 and 4 and Comparative Example 1
A substrate using the core substrate 2 of Comparative Example 2 was used as Comparative Example 2. still,
Examples 1 and 2 and Comparative Example 1 satisfy Expression 7, and Examples 3, 4 and Comparative Example 2 satisfy Expression 8. For each of the three prepared for each example, +
A reliability (thermal shock) test of heating and cooling between 125 ° C. and −55 ° C. 1000 times (cycles) was performed. In this test, whether or not cracks occurred in the resin 11 of each example was observed after completion of 1,000 times. Table 1 shows the results.

[0031]

[Table 1]

According to the results shown in Table 1, in Examples 1 to 4,
In all cases, cracks did not occur in the resin 11, whereas in Comparative Examples 1 and 2, all three cracks occurred in the resin 11. From these results, the coefficient of thermal expansion α1, of the core substrate 2, the resin 11, the chip capacitor 12, and the IC chip 38
It is understood that it is important that α2, α3, and α4 satisfy the above Expressions 7 and 8, and that the thermal expansion coefficient α2 of the resin 11 be 40 ppm / ° C. or less, preferably 35 ppm / ° C. or less. Thus, it can be easily understood that the effect of the wiring board of the present invention is supported.

FIG. 4 relates to main steps of a manufacturing method for a wiring board of a different form. In the following, the same reference numerals are used for the same parts and elements as in the above embodiment.
FIG. 4A shows a state in which the same electronic component unit 10 is inserted into a concave portion 44 opened on the surface 41 side of a core substrate (wiring substrate main body) 40 containing glass cloth. The core substrate 40 having the concave portion 44 is formed by previously laminating a thick insulating plate (not shown) having a through hole and a thin flat insulating plate via an adhesive sheet, and heating and crimping. However, the concave portion 44 may be formed from a single insulating plate by spot facing using a router or the like. As shown in FIG. 4A, a plurality of through holes 4 are provided between the bottom surface 45 of the concave portion 44 and the back surface 42 of the core substrate 40.
6 penetrates, and in each hole 46, a cylindrical through-hole conductor 48 and a filling resin 47 are formed to penetrate.

As shown in FIG. 4B, the upper end of each through-hole conductor 48 and the electrode 16 on the bottom surface of each capacitor 12 of the inserted electronic component unit 10 are connected to Sn-
They are individually connected in advance via a brazing material (low melting point alloy) 49 made of an Ag-based alloy. In this state, after the melted resin 11 is injected into the concave portion 44, a curing process is performed. As a result, as shown in FIG. 4B, the electronic component unit 10 is fixed and embedded in the solidified resin 11 in the concave portion 44 and is embedded in the concave portion 44. Further, the raised surface 11a of the resin 11 is polished and flattened to form a newly formed resin 11 as shown in FIG.
The upper end surface of the electrode 14 of each capacitor 12 in the unit 10 is exposed on the surface 11c.

Thereafter, as shown in FIG. 1, the build-up of the wiring layers 20, 21 and the like on the front and back surfaces 41, 42 of the core substrate 40, such as the insulating layers 22, 23 shown in FIG. Layers BU1, BU2 and filled via conductor 2
4, 25, etc. are formed. At this time, each electrode 14 is connected to the wiring layer 20, and the lower end of the through-hole conductor 48 is connected to the wiring layer 21/27. 1, a through-hole conductor 8 (not shown) penetrating between the front and rear surfaces 41, 42 of the core substrate 40 is formed, and the bumps are formed on the first and second main surfaces 34a, 35a. 36 and wiring
(Connection terminals) 37 are formed. As a result, a wiring board including the core board 40 in which the electronic component unit 10 having the plurality of chip capacitors 12 in the recess 44 is obtained.

The thermal expansion coefficient α of the core substrate (wiring substrate body) 40, resin 11, and chip capacitor (electronic component) 12
1, α2 and α3 are set under the relationship of the above equation (7). Further, the IC chip (semiconductor element) 38 and the insulating layer 2
The coefficients of thermal expansion α4 and α5, such as 2, are set in accordance with the relationship of the above formula 8 or formula 9. In the present embodiment, the thermal expansion coefficient α of the wiring substrate body (core substrate) 40 is 1:16 ppm /
° C, thermal expansion coefficient α2 of resin 11: 23 ppm / ° C, thermal expansion coefficient α3 of chip capacitor (electronic component) 12: 8 ppm /
° C, thermal expansion coefficient α4: 4p of IC chip (semiconductor element) 38
pm / ° C., coefficient of thermal expansion α5 of the insulating layer 22: 60 ppm
/ ° C.

The present invention is not limited to the embodiments and examples described above. For example, the electronic components include passive components such as inductors, resistors, and filters, low-noise amplifiers (LNA), memories, semiconductor devices,
Active components such as FETs or transistors, or SAW filters, LC filters, antenna switch modules, diplexers, etc., or chips of these, and different types of these in the same through-hole or recess It may be built in. Also, electronic components
Only one may be built in the through-hole or recess of the wiring board body (core board). In this case, the electrodes of the electronic component can be connected to the wiring layer and the lands connected to the wiring layer by soldering.

Further, a plurality of through holes or concave portions may be formed in the wiring substrate body (core substrate), or the through holes and the concave portions may be provided adjacent to each other. The material of the wiring board body (core board) 2 and 40 is
In addition to the glass-epoxy resin composite material, similar heat resistance, mechanical strength, flexibility, glass woven fabric having the ease of processing and the like, glass fiber and epoxy resin such as glass woven fabric,
A glass fiber-resin material which is a composite material with a resin such as a polyimide resin or a BT resin may be used. Alternatively, a composite material of an organic fiber and a resin such as a polyimide fiber, or a resin-resin composite material in which a resin such as an epoxy resin is impregnated into a fluororesin having a three-dimensional network structure such as PTFE having continuous pores may be used. It is possible.

Further, the material of the insulating layers 22 and 23 may be a polyimide resin, a BT resin, a PPE resin, or a continuous pore having the same heat resistance, pattern moldability, and the like, in addition to the epoxy resin as a main component. PTFE having
For example, a resin-resin composite material in which a resin such as an epoxy resin is impregnated into a fluorine resin having a three-dimensional network structure can be used. Further, the material of the wiring layers 20, 21 and the like may be Ni, Ni-Au, or the like in addition to the copper plating, or may be formed by applying a conductive resin without using metal plating. It is also possible. Further, as the connection terminals to the IC chip 38, in addition to the flip chip bumps 36, those formed with flip chip pads, wire bonding pads, or TAB connection pads may be used.

Further, in the capacitor of the electronic component 12,
Is BaTiO₃High dielectric ceramics
Used, but PbTiO₃, PbZrO₃, TiO₂, S
rTiO₃, CaTiO₃, MgTiO₃, KNb
O₃, NaTiO₃, KTaO₃, PbTaO₃, (N
a_1/2Bi_1/2) TiO₃, Pb (Mg_1/2W
_1/2) O ₃, (K_1/2Bi_1/2) TiO₃Mainly
What is used as a component may be used. Further, the electronic component 1
The material of the second electrodes 14 and 16 was mainly composed of Cu,
Pt, Ag, Ag-P compatible with the electronic component 12
t, Ag-Pd, Cu, Au, Ni, etc.
it can. In addition, the capacitor 12 of the electronic component has a high
Dielectric layer mainly composed of dielectric ceramic or Ag-Pd
Electrode layer made of resin, Cu plating, Ni plating
Condensed with via conductors and wiring layers
It is good also as what was made. The wiring board of the present invention
Are the front surfaces 3, 41 and the back surfaces 4, 4 of the core substrates 2, 40.
2 has only wiring layers 20 and 21 and insulating layers 22 and 23
Is included.

[0041]

The wiring board of the present invention described above.
According to the first aspect, the coefficient of thermal expansion of the wiring board body (core board) is larger than that of the built-in electronic component, and is equal to or smaller than that of the resin in which the electronic component is embedded. Also have a small relationship. For this reason, in order to solidify the melted resin, or when heating at a separate position, even if the electronic component expands, the wiring board body and the resin expand further, so that the through-holes or recesses of the wiring board body, Alternatively, the size of the resin that surrounds and houses the electronic component increases. Therefore, it is possible to prevent the resin or the wiring board main body from being broken or damaged, so that the conduction between the built-in electronic component and the internal wiring layer can be stably and reliably obtained.

According to the second aspect of the present invention, in addition to the above, since the coefficient of thermal expansion of the semiconductor element is equal to or less than the coefficient of thermal expansion of the built-in electronic component, for example, At the time of soldering when mounting a semiconductor element on a main surface or the like, even if the semiconductor element expands thermally, its coefficient of thermal expansion is equal to or less than that of the electronic component. For this reason, it does not affect the resin in which the wiring board body and the electronic components are embedded. Therefore, the mounted semiconductor element and the electronic component can be reliably and stably conducted directly or via an internal wiring layer, and the wiring substrate can be efficiently manufactured.

Further, according to the wiring board of the third aspect, in addition to the above relationships, the insulating layer thermally expands to the same degree or more than the resin, so that the insulating layer may be solidified when the resin is solidified or at a separate position. When the electronic component, the wiring board main body, and the resin expand during heating, the insulating layer expands further more than these. For this reason, since the expansion of the resin or the like can be absorbed, it is possible to prevent the resin or the wiring board body from being broken or damaged.
Therefore, it is possible to stably and reliably establish conduction between the electronic component and the wiring layer between the insulating layers. In addition, according to the wiring board of the fourth aspect, it is possible to prevent the resin or the wiring board body from being cracked or damaged, and to more reliably prevent the expansion of the semiconductor element from affecting the wiring board body. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a wiring board according to one embodiment of the present invention.

FIG. 2 is a perspective view of an electronic component unit built in the wiring board of FIG. 1;

FIGS. 3A to 3C are schematic diagrams showing main steps in a method of manufacturing the wiring board of FIG. 1;

FIGS. 4A to 4C are schematic views showing main steps in a method of manufacturing a wiring board of a different form.

FIGS. 5A and 5B are schematic diagrams showing a conventional wiring board.

[Explanation of symbols]

1 ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… 3,41 ……… Front 4,42 ………………… Back side 6 ………………………………………………………………… Through-hole 12 …………… Chip capacitors
(Electronic components) 11 Resin 22, 23, 28, 29, 34, 35 Insulating layer 34a ............... First Main surface (above the surface of the main body of the wiring board) 38 IC chip (semiconductor element) 44 …………………… Recess

Claims (4)

[Claims] 1. An insulative wiring board main body having front and back surfaces, a through hole or a recess provided in the wiring board main body, and an electronic component incorporated in the through hole or the recess and fixed via a resin. And the thermal expansion coefficient α of the wiring board body, the resin, and the electronic component.
1, wherein α1, α2 and α3 have a relationship represented by Expression 1. Equation 1 α3 <α1 ≦ α2 2. An insulative wiring board body having front and back surfaces, a through hole or a recess provided in the wiring board body, and an electronic component incorporated in the through hole or the recess and fixed via a resin. And a semiconductor element mounted above the surface of the wiring board main body and electrically connected to the electronic component, and the thermal expansion coefficients α1, α2, of the wiring board main body, the resin, the electronic component, and the semiconductor element. α3, α4 have a relationship represented by the following equation (2). ## EQU2 ## α4 ≦ α3 <α1 ≦ α2 3. An insulative wiring board body having front and back surfaces, a through hole or a recess provided in the wiring board body, and an electronic component incorporated in the through hole or the recess and fixed via a resin. And an insulating layer formed on at least one of the front surface and the back surface of the wiring board body, and the thermal expansion coefficients α1, α2, α3 of the wiring board body, the resin, the electronic component, and the insulating layer. , Α5 have the relationship of Equation 3. Equation 3 α3 <α1 ≦ α2 ≦ α5 4. A resin having a coefficient of thermal expansion α2 of 40 ppm /
The wiring board according to claim 1, wherein the temperature is lower than ℃.