JP2009054621A - Mulilayer wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer wiring board capable of reducing its warpage in reflow soldering even if a space for forming a dummy pattern is not enough. <P>SOLUTION: The multilayer wiring board 100 includes first to nth wiring layers made of a copper wiring 101 and a resin 103, and resin layer first to (n-1)th layers made of a reinforced fiber bundle 102 and a resin 103. The wiring board 100 has a structure in which at least one of the resin base material layers is allowed to have an equivalent longitudinal elastic modulus and an equivalent linear expansion coefficient different from those of the other layers, the sum of bending moment at a unit temperature change as a drive force of warpage in reflow soldering is smaller than a value C (MPa×mm<SP>2</SP>×°C<SP>-1</SP>) determined by the limit amount of board warpage capable of mounting an electronic component to be mounted on the board. Thus, the warpage of the board can be reduced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a multilayer wiring board composed of two or more wiring layers on which electronic components are mounted.

  The multilayer wiring board is composed of copper and resin, and is reinforced with a resin layer for the purpose of constructing complex electronic circuits with high density and mounting various electronic components on it with high density. This is a member for electronic devices having a structure in which resin base material layers composed of fiber bundles are alternately stacked, and is widely used in various digital devices and mobile devices.

  First, the structure of a general multilayer wiring board will be described. FIG. 6 is a diagram showing a configuration of a conventional multilayer wiring substrate 200 (hereinafter referred to as a substrate 200) having n wiring layers and (n-1) resin base material layers between the n wiring layers. As shown in FIG. 6, the substrate 200 is generally formed of a wiring layer 104 (consisting of copper wiring 101 and resin 103) and a resin base layer 105 (comprising reinforcing fiber bundle 102 and resin 103). In the reflow soldering process, the substrate 200 is placed on a reflow belt or a reflow pallet together with the mounted components, heated from room temperature to 220 ° C. or higher and soldered, and then lowered to room temperature again. At this time, the substrate 200 has two types of coefficients determined by the contents of copper and resin constituting the wiring layer 104, that is, an equivalent longitudinal elastic coefficient indicating the average rigidity of each wiring layer 104, and a unit temperature change. The bending moment generated by the difference from the equivalent linear expansion coefficient indicating the average expansion coefficient becomes a driving force and warpage occurs. If an electronic component is mounted with the substrate warped during the reflow soldering process, the connection reliability between the electronic component and the substrate will be significantly reduced, which is pointed out as an industry quality problem. Has been.

  Hereinafter, the bending moment, which is the driving force for the substrate warpage during a thermal load such as reflow soldering, will be described.

In FIG. 6, the thickness of the kth wiring layer (wiring layer kth layer) counted from one end face of the substrate 200 is t _k (mm), and the wiring layer kth layer from the midpoint FC in the stacking direction of the substrate 200. A direction in the plane of the midpoint fk substrate 200 in the stacking direction and coordinate axes orthogonal to the direction are defined as an x-axis and a y-axis. Next, it is determined by the content of copper and resin in the kth layer of the wiring layer, and the equivalent longitudinal elastic modulus indicating the average stiffness in the x-axis direction and the y-axis direction is expressed by e _kx (MPa), e _ky (MPa), An equivalent linear expansion coefficient indicating an average expansion coefficient with respect to a unit temperature change is defined as a _kx (° C. ⁻¹ ) and a _ky (° C. ⁻¹ ).

  In the conventional substrate 200, it is common to use a type of resin base material layer in which there is no difference between the equivalent longitudinal elastic modulus and the equivalent linear expansion coefficient. In such a substrate 200, the resin base material layer 105 is used. No bending moment occurs at.

  Therefore, the driving force of the substrate warp at the time of thermal load is expressed only by the bending moment generated by the difference in the remaining copper ratio in each layer of the wiring layer 104. The bending moments when the unit temperature changes in the x-axis direction and the y-axis direction generated in the wiring layer 104 are expressed by Mx number 4) and (number 5), respectively.

Further, in order to make it possible to mount an electronic component on the substrate 200, as shown in the following (Equation 6) and (Equation 7), the bending moment M _x (MPa · mm ² · ° C. ⁻¹ ), M _y a ^{(MPa · mm 2 · ℃ -1} ), needs to be smaller than a value determined ^{C (MPa · mm 2 · ℃} -1) by the substrate warpage limit that can mount electronic components.

と表される。 The above value C (MPa · mm ² · ° C. ⁻¹ ) is obtained empirically by experiments. For example, when the same electronic component is mounted on a plurality of types of substrates having different warpage amounts during reflow soldering because the remaining copper ratio in each wiring layer of the substrate is different, the length s ( In the range of mm), when the amount of warpage of the substrate is larger than d (mm), mounting failure of the electronic component occurs, and when the amount of warping is less than d (mm), the mounting failure of the electronic component does not occur. . At this time, the equivalent longitudinal elastic modulus indicating the average rigidity of the substrate is E (MPa), the secondary moment of inertia indicating the ease of deformation of the cross section of the substrate is I (mm ³ ), and the electronic component is bonded to the substrate. Assuming that the amount of temperature change before and after soldering is ΔT (° C.), the value C (MPa · mm ² · ° C. ⁻¹ ) is

It is expressed.

Conventionally, as shown in Patent Document 1, an electronic circuit is configured in the wiring layer 104 of the multilayer wiring board 200 in order to suppress the warpage of the board due to the generation of a bending moment due to the difference in the remaining copper ratio in each wiring layer. Measures have been taken to form a dummy pattern 106 that is not the original copper wiring and to make the remaining copper ratio as uniform as possible in each layer of the wiring layer.
Japanese Unexamined Patent Publication No. 2000-151035 (page 2-3, FIG. 1)

  However, it is not possible to secure a sufficient space for providing a dummy pattern in the wiring layer for a substrate for a small electronic device that requires a particularly high-density electronic circuit, thereby reducing the warpage of the multilayer wiring substrate. Had the problem of being difficult.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a multilayer wiring board capable of reducing warpage even when there is no space for providing a dummy pattern in a wiring layer.

  In order to solve the above-mentioned problem, a multilayer wiring board (substrate) according to the first claim of the present application has a wiring layer and a resin base material layer alternately stacked, and the uppermost surface and the lowermost surface in the stacking direction are the wirings. A multilayer wiring board (hereinafter, referred to as a board) composed of the resin base material layers that are different in at least one layer of the plurality of resin base material layers, and the following (Equation 1): (Equation 2) is satisfied, and substrate warpage in reflow soldering is reduced.

t _k (mm): the thickness r _k (mm) of the kth wiring layer (wiring layer k-th layer) counted from one end face of the substrate: the wiring layer number from the midpoint FC in the stacking direction of the substrate Distance T _k (mm) to the middle point f _{k in} the stacking direction of the k layer: the thickness R _{k of the} k-th resin base layer (resin base layer k-th layer) counted from one end face of the substrate mm): the distance from the midpoint FC to the midpoint F _k in the stacking direction of said resin base layer first k layer ^{C (MPa · mm 2 · ℃} -1): substrate limit that can mount electronic components on the substrate Values e _kx (MPa) and e _ky (MPa) determined by the amount of warpage: Equivalent longitudinal length determined by the content of copper and resin in the kth layer of the wiring layer and indicating average stiffness in the x-axis direction and the y-axis direction Elastic modulus a _kx (° C. ⁻¹ ), a _ky (° C. ⁻¹ ): determined by the content of copper and resin in the kth layer of the wiring layer, and the unit of x axis direction and y axis direction. Equivalent linear expansion coefficients E _kx (MPa) and E _ky (MPa) indicating an average expansion coefficient with respect to the temperature change: x axis determined by the contents of the resin and the reinforcing fiber bundle in the kth layer of the resin base material layer Direction and y-axis direction equivalent longitudinal elastic modulus A _kx (° C. ⁻¹ ), A _ky (° C. ⁻¹ ): x axis direction determined by the content of the resin and the reinforcing fiber bundle in the kth layer of the resin base material layer And the equivalent linear expansion coefficient in the y-axis direction (the x-axis and the y-axis orthogonal to each other in the plane orthogonal to the stacking direction of the substrates)

In the multilayer wiring board (substrate) according to the second claim of the present application, the value C (MPa · mm ² · ° C. ⁻¹ ) satisfies the following (Equation 3).

ｌ（ｍｍ）：前記基板に実装される最大寸法を備えた電子部品の最大寸法
ｈ（ｍｍ）：前記電子部品と前記基板とを接合するはんだの高さ
Ｅ（ＭＰａ）：前記基板の平均的な剛性を示す等価縦弾性係数
Ｉ（ｍｍ³）：前記基板の断面の変形のしやすさを示す断面二次モーメント
ΔＴ（℃）：電子部品のはんだ付け前後の前記基板の温度変化量

l (mm): Maximum dimension h (mm) of an electronic component having the maximum dimension mounted on the substrate: Solder height E (MPa) for joining the electronic component and the substrate: Average of the substrate Equivalent longitudinal elastic modulus I (mm ³ ) indicating the rigidity: cross-sectional secondary moment ΔT (° C.) indicating the ease of deformation of the cross-section of the substrate: temperature change amount of the substrate before and after soldering of the electronic component

With this mathematical formula 3, it is possible to obtain the value C (MPa · mm ² · ° C. ⁻¹ ) through various mounting experiments without empirically deducing the limit amount of substrate warpage.

  As described above, the multilayer wiring board (substrate) of the present invention has a resin base material layer having a plurality of different equivalent longitudinal elastic modulus and equivalent linear expansion coefficient, and changes the unit temperature of the wiring layer and the resin base material layer. By making the bending moment less than a value determined by the limit amount of substrate warp that allows electronic components to be mounted on the substrate, there is an effect of reducing the substrate warp in reflow soldering.

  Hereinafter, Embodiment 1 of the present invention will be described with reference to FIG. 1 and FIG.

(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a multilayer wiring board 100 according to Embodiment 1 of the present invention. The multilayer wiring substrate 100 (hereinafter referred to as the substrate 100) has n wiring layers from wiring layers 1, 2,..., N in order from the bottom, and a resin base material in order from the bottom between the wiring layers. Layers 1, 2, ..., (n-1) up to (n-1) resin base material layers are provided. In the substrate 100, the wiring layer 104 is formed of the copper wiring 101 and the resin 103, and the resin base material layer 105 is formed of the reinforcing fiber bundle 102 and the resin 103.

Here, the thickness of the k-th wiring layer (wiring layer k-th layer) counted from one end face of the substrate 100 is t _k (mm), and the wiring layer k-th layer from the midpoint FC in the stacking direction of the substrate 100 is set. The distance to the middle point f _{k in the} stacking direction is r _k (mm), and the thickness of the k-th resin base layer (resin base layer k-th layer) counted from one end face of the substrate 100 is T _k (mm). ), And the distance from the midpoint FC to the center plane F _k located at the center in the thickness direction of the resin base material layer k-th layer is R _k (mm).

  Next, FIG. 2A is a diagram showing the configuration of the wiring layer 104. Specifically, the k-th wiring layer 104 (wiring layer k-th layer) counted from one end face of the substrate 100 is 1. The layer is extracted. FIG. 2B is a diagram showing the configuration of the resin base material layer 105, specifically, the k-th resin base material layer 105 (resin base material layer k-th layer counted from one end face of the substrate 100). ) Is extracted. In addition, in FIG. 1, the fiber bundle orientation angle of the resin base material layer first layer and the fiber bundle content of the resin base material layer second layer are represented by the other resin base material layer third layer to the (n-1) layer. Different states in which the equivalent longitudinal elastic modulus and the equivalent linear expansion coefficient of the resin base material layer first layer and the resin base material layer second layer are different from those of the resin base material layer third to (n-1) layers. Is shown.

A certain direction in the substrate surface (surface orthogonal to the substrate stacking direction) is defined as the x axis, and a coordinate axis in the substrate surface orthogonal to the x axis is defined as the y axis. In FIG. The coefficient is E _PP (MPa), the linear expansion coefficient is A _PP (° C. ⁻¹ ), the longitudinal elastic modulus of the copper wiring 101 is e _Cu (MPa), the linear expansion coefficient is a _Cu (° C. ⁻¹ ), and the wiring layer number k When the remaining copper ratio of the layer is V _Cuk and the wiring angle is q _k (°), the equivalent longitudinal elastic modulus e _kx (MPa) and e _ky (MPa) with respect to the x-axis and y-axis in the wiring layer k-th layer The expansion coefficients a _kx (° C. ⁻¹ ) and a _ky (° C. ⁻¹ ) are respectively expressed by the following equations.

2B, the longitudinal elastic modulus of the resin 103 is E _PP (MPa), the linear expansion coefficient is A _PP (° C. ⁻¹ ), the longitudinal elastic modulus of the reinforcing fiber bundle 102 is E _F (MPa), Assuming that the expansion coefficient is A _F (° C. ⁻¹ ), the fiber bundle content of the resin base layer k-th layer is V _Fk , and the fiber bundle orientation angle is Q _k (°), the x axis in the resin base layer k-th layer , Y-axis equivalent longitudinal elastic modulus E _kx (MPa), E _ky (MPa) and equivalent linear expansion coefficient A _kx (° C. ⁻¹ ), A _ky (° C. ⁻¹ ) are respectively expressed by the following equations.

The conventional multilayer wiring board 200 shown in FIG. 6 described above has the same type with no difference in the equivalent longitudinal elastic modulus and equivalent linear expansion coefficient of each resin base material layer 105 shown in (Equation 13) to (Equation 16). there were. Accordingly, the (number 4), (5) when the unit temperature change due to the difference in copper remaining rate in each wiring layer 104 shown in bending moment ^{_{M x (MPa · mm 2 ·}} ℃ -1), M y ( for ^{MPa · mm 2 · ℃ -1)} , in order to satisfy the equation (6), (7) is by changing the electric circuit design according to the installation of the dummy pattern, reduce the difference between the residual copper rate of the wiring layers 104 There was a need to do.

On the other hand, the substrate 100 of the present invention has the fiber bundle content rate or the fiber bundle orientation angle or both for at least one of the resin base layers 105 with respect to the value C (MPa · mm ² · ° C. ⁻¹ ). Different from those of the other resin base material layers 105, a substrate having a plurality of types of equivalent longitudinal elastic modulus and equivalent linear expansion coefficient is formed, and for each of the x-axis and y-axis directions, ) And (Equation 2) are satisfied.

  (Equation 1) and (Equation 2) are the sum (left side) of the bending moment at the time of unit temperature change in each wiring layer 104 and each resin base layer 105 and the value C (right side) with respect to the x-axis and y-axis, respectively. The relationship between the resin base material layers 105 shown in the second term on the left side with respect to the bending moment when the unit temperature changes due to the difference in the remaining copper ratio in each wiring layer 104 shown in the first term on the left side. (Equation 1) and (Equation 2) are established by canceling out the bending moment when the unit temperature changes due to the difference between the equivalent longitudinal elastic modulus and the equivalent linear expansion coefficient. This makes it possible to reduce the total sum of the bending moments without the need to reduce the size of the first term on the left side of (Equation 1) and (Equation 2) by changing the electrical circuit design. To reduce.

Hereinafter, an example of a design method for realizing the first embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing an example of a design method for realizing the first embodiment of the present invention. When the above-mentioned value targeted for the invention is C ₁ (MPa · mm ² · ° C. ⁻¹ ), (Expression 1) and (Expression 2) are expressed by the following equations.

  First, the remaining copper ratio of each wiring layer is extracted from a substrate CAD (Computer Aided Design) including design data of the substrate 10 (step S1).

  Next, the wiring direction of each wiring layer is determined according to the definition of the x-axis and y-axis of the substrate CAD (step S2).

  In the equations for calculating the equivalent longitudinal elastic modulus and equivalent linear expansion coefficient of the wiring layer 104 shown in (Equation 9) to (Equation 12), the longitudinal elastic modulus and the linear expansion coefficient of the copper wiring 101 and the resin 103, and the wiring layers 104. The remaining copper ratio and the wiring direction are substituted (step S3).

Next, the equivalent longitudinal elastic modulus and the equivalent linear expansion coefficient of each wiring layer 104 obtained above are substituted into (Equation 17) and (Equation 18). At this time, both the first terms on the left side of (Equation 17) and (Equation 18) are constants. The first term on the left side of (Equation 17) is a constant K _x1 , and the first term on the left side of ( _Equation 18) is K _y1 (step S4).

Focusing on the first layer of the resin base material layer, consider obtaining the fiber bundle content and the fiber bundle orientation angle of the first layer of the resin base material layer so as to satisfy (Equation 19) and (Equation 20). Reinforcement of the resin base material layer 105 of k = 2 to (n−1) layers in the calculation formulas of the equivalent longitudinal elastic modulus and the equivalent linear expansion coefficient of the resin base material layer 105 shown in (Expression 13) to (Expression 16). The longitudinal elastic modulus and linear expansion coefficient of the fiber bundle 102 and the resin 103, and the fiber bundle content and the fiber bundle orientation angle are substituted and calculated (step S5), and the thickness T ₁ of the first layer of the resin base material layer is calculated. Substituting into (Equation 19) and (Equation 20) together with the distance R ₁ from the midpoint FC to the midpoint F ₁ of the first layer of the resin base material layer, (Equation 17) and (Equation 18) are as follows: It is expressed in

Here, K _x2 , K _x3 , K _y2 , and K _y3 are constant terms calculated by the above substitution calculation. From (Equation 13) to (Equation 16), (Equation 21) and (Equation 22) are both functional expressions having Q ₁ (°) and V _F1 as variables.

By solving (Equation 21) and (Equation 22) as simultaneous equations concerning Q ₁ (°) and V _F1 , the fiber bundle orientation angle of the first layer of the resin base material layer satisfying (Equation 17) and (Equation 18) Q ₁ (°) and the fiber bundle content V _F1 can be obtained (step S6). According to this design method, since the configuration of the resin base material layer 105 that realizes the first embodiment can be obtained based on the design data of the substrate CAD before the substrate is manufactured, the prototype of the substrate 100 is repeated and warped sequentially. There is no need to evaluate and redesign the quantity.

  Next, in the resin base material layer 105 of the multilayer wiring substrate 100, an example of the effect of reducing the warpage of the substrate by making one layer different from the other layer was confirmed by numerical analysis simulation. FIG. 5A is a diagram showing a mathematical analysis simulation result of a conventional multilayer wiring board, and FIG. 5B is a mathematical analysis simulation result of the multilayer wiring board according to Embodiment 1 of the present invention. FIG.

First, the longitudinal elastic modulus of the copper wiring is 50000 (MPa), the linear expansion coefficient is 17 × 10 ⁻⁶ (° C. ⁻¹ ), the longitudinal elastic modulus of the resin is 8000 (MPa), and the linear expansion coefficient is 60 × 10 ⁻⁶ ( ° C. ^-1), 70000 a longitudinal elastic modulus of the reinforcing fiber bundle (MPa), using a multilayer wiring board to the linear expansion coefficient of ^{5 × 10 -6 (℃ -1)} , was warpage simulation during reflow soldering Results are shown. FIG. 5A shows a multilayer wiring board having a conventional configuration, in which the remaining copper ratio of the wiring layer is different from 20%, 20%, 25%, and 50% when counted from the lower surface of the board, whereas the resin base material is shown. The fiber bundle content of the layers is the same for all layers.

  On the other hand, FIG. 5B shows that the remaining copper ratio of the wiring layer is different from 20%, 20%, 25%, and 50% when counted from the lower surface of the substrate, whereas the first resin group counted from the lower surface of the substrate. Only the material layer is a multilayer wiring board in which the fiber bundle content is 40% less than that of the other resin base material layers. The lower side of FIGS. 5A and 5B is a graph of the warped shape in the simulation results. In FIG. 5A, the warp amount is 0.283 (mm). On the other hand, FIG. 5B shows a warpage amount of 0.056 (mm), and it can be seen that the warpage of about 80% is reduced by the present invention.

  Here, when the calculation shown in FIG. 5A is applied to the left side of the above-described (Equation 1) and (Equation 2), the following equations (Equation 23) and (Equation 24) are obtained.

  Similarly, when the configuration of FIG. 5B is calculated by the same formula, the results of (Equation 25) and (Equation 26) are obtained.

The value C in this example is empirically known to be 1.03 × 10 ⁻⁵ (MPa · mm ² · ° C. ⁻¹ ). 5 (a) does not satisfy (Equation 1) and (Equation 2), but the configuration of FIG. 5 (b) satisfies the same equation, and the multilayer wiring board 100 of the present invention mounts electronic components. You can see that

  Although not described here, for at least one of the resin base layers, the equivalent longitudinal elastic modulus and the equivalent linear expansion coefficient are changed by changing the fiber bundle orientation angle, and (Equation 1) and (Equation 2) are changed. It is clear that the substrate warpage at the time of reflow is also reduced in the substrate having a satisfactory configuration.

(Embodiment 2)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a diagram showing the relationship between the multilayer wiring board and the shape of the electronic component mounted thereon, and the maximum dimension l (mm) of the substrate 100 and the electronic component 107 having the maximum dimension mounted thereon, The relationship between the height of the solder 108 for joining the electronic component and the substrate 100 to h (mm) is shown.

が導かれる。一方、はり理論式より、単位温度変化時の曲げモーメントＮ（ＭＰａ・ｍｍ²・℃^-1）が生じる場合の曲率半径Ｒ_b（ｍｍ）は、前記基板の平均的な剛性を示す等価縦弾性係数をＥ（ＭＰａ）、前記基板の断面の変形のしやすさを示す断面二次モーメントをＩ（ｍｍ³）、温度変化量をΔＴ（℃）とするとき、

と表される。曲率半径Ｒ_a（ｍｍ）とＲ_b（ｍｍ）は同じものを表すことから、両者を等式で結ぶことにより、

が成立する。前述の（数７）の左辺に示す配線層と樹脂基材層に関する曲げモーメントが（数２２）に示すモーメントＮ（ＭＰａ・ｍｍ²・℃^-1）より大きければ、前記基板は、前記最大寸法ｌ（ｍｍ）の間ではんだ高さｈ（ｍｍ）を越える反りを生じることを示すため、請求項１記載の値Ｃ（ＭＰａ・ｍｍ²・℃^-1）を、

となる構成とすることで、電子部品と基板の間の接続信頼性を保つことができるまで基板反りを低減することができる。本実施の形態２によれば、従来実施されてきたように、複数種の基板を用いた種々の実験を行う必要なく、簡便に前記値Ｃ（ＭＰａ・ｍｍ²・℃^-1）を求めることが可能となる。 If warpage exceeding the solder height h (mm) occurs between the maximum dimensions l (mm) of the component due to warpage of the substrate 100 during reflow soldering, the connection between the electronic component and the multilayer wiring board It is known that reliability is significantly reduced. When the curvature radius of the multilayer wiring board when the warp of the solder height h (mm) occurs between the maximum dimensions l (mm) is R _a (mm),

Is guided. On the other hand, the radius of curvature R _b (mm) when the bending moment N (MPa · mm ² · ° C. ⁻¹ ) at the time of unit temperature change is calculated from the beam theory equation is equivalent longitudinal elasticity indicating the average rigidity of the substrate. When the coefficient is E (MPa), the cross-sectional secondary moment indicating the ease of deformation of the cross-section of the substrate is I (mm ³ ), and the temperature change is ΔT (° C.),

It is expressed. Since the radii of curvature R _a (mm) and R _b (mm) represent the same thing,

Is established. If the bending moment related to the wiring layer and the resin base material layer shown on the left side of (Expression 7) is larger than the moment N (MPa · mm ² · ° C. ⁻¹ ) shown in (Expression 22), the substrate has the maximum dimension. In order to show that the warpage exceeding the solder height h (mm) occurs between 1 (mm), the value C (MPa · mm ² · ° C. ⁻¹ ) according to claim 1 is

With this configuration, it is possible to reduce substrate warpage until connection reliability between the electronic component and the substrate can be maintained. According to the second embodiment, the value C (MPa · mm ² · ° C. ⁻¹ ) can be easily obtained without performing various experiments using a plurality of types of substrates, as conventionally performed. Is possible.

  The multilayer wiring board of the present invention has a resin base layer having a plurality of different equivalent longitudinal elastic coefficients and equivalent linear expansion coefficients, and the bending moment at the time of unit temperature change with respect to the wiring layer and the resin base layer is determined by the multilayer wiring board. By making it smaller than the value determined by the limit of the amount of board warpage that can mount electronic components on the board, it has the effect of reducing board warpage during reflow soldering. It can also be applied to uses such as multilayer wiring boards mounted for circuit formation.

The figure for demonstrating the structure of the multilayer wiring board in connection with Embodiment 1 of this invention. (A) The figure which showed the structure of the wiring layer, (b) The figure which showed the structure of the resin base material layer The figure which showed the relationship between the multilayer wiring board in connection with Embodiment 2 of this invention, and the shape of the electronic component mounted on it The flowchart which shows an example of the design method which implement | achieves Embodiment 1 of this invention. (A) The figure which showed the mathematical analysis simulation result of the conventional multilayer wiring board, (b) The figure which showed the mathematical analysis simulation result of the multilayer wiring board in Embodiment 1 of this invention Diagram showing the configuration of a conventional multilayer wiring board

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Multilayer wiring board 101 Copper wiring 102 Reinforcing fiber bundle 103 Resin 104 Wiring layer 105 Resin base layer 106 Dummy pattern 107 Electronic component 108 Solder 200 Conventional multilayer wiring board

Claims (2)

The resin base material layer in which the wiring layers and the resin base material layers are alternately laminated, the uppermost surface and the lowermost surface in the stacking direction are the wiring layers, and at least one material of the plurality of resin base material layers is different. A multilayer wiring board (hereinafter, referred to as a substrate) configured by the following (Formula 1) and (Formula 2):

t _k (mm): the thickness r _k (mm) of the kth wiring layer (wiring layer k-th layer) counted from one end face of the substrate: the wiring layer number from the midpoint FC in the stacking direction of the substrate Distance T _k (mm) to the middle point f _{k in} the stacking direction of the k layer: the thickness R _{k of the} k-th resin base layer (resin base layer k-th layer) counted from one end face of the substrate mm): the distance from the midpoint FC to the midpoint F _k in the stacking direction of said resin base layer first k layer ^{C (MPa · mm 2 · ℃} -1): substrate limit that can mount electronic components on the substrate Values e _kx (MPa) and e _ky (MPa) determined by the amount of warpage: Equivalent longitudinal length determined by the content of copper and resin in the kth layer of the wiring layer and indicating average stiffness in the x-axis direction and the y-axis direction Elastic modulus a _kx (° C. ⁻¹ ), a _ky (° C. ⁻¹ ): determined by the content of copper and resin in the kth layer of the wiring layer, and the unit of x axis direction and y axis direction. Equivalent linear expansion coefficients E _kx (MPa) and E _ky (MPa) indicating an average expansion coefficient with respect to the temperature change: x axis determined by the contents of the resin and the reinforcing fiber bundle in the kth layer of the resin base material layer Direction and y-axis direction equivalent longitudinal elastic modulus A _kx (° C. ⁻¹ ), A _ky (° C. ⁻¹ ): x axis direction determined by the content of the resin and the reinforcing fiber bundle in the kth layer of the resin base material layer And the equivalent linear expansion coefficient in the y-axis direction (the x-axis and the y-axis orthogonal to each other in the plane orthogonal to the stacking direction of the substrates) The multilayer wiring board according to claim 1, wherein the value C (MPa · mm ² · ° C. ⁻¹ ) satisfies the following (Equation 3).

l (mm): Maximum dimension h (mm) of an electronic component having the maximum dimension mounted on the substrate: Solder height E (MPa) for joining the electronic component and the substrate: Average of the substrate Equivalent longitudinal elastic modulus I (mm ³ ) indicating the rigidity: cross-sectional secondary moment ΔT (° C.) indicating the ease of deformation of the cross-section of the substrate: temperature change amount of the substrate before and after soldering of the electronic component

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