JPH10107398A - Structure of implementation on wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of implementation on a wiring board of a high degree of reliability by which a firm and stable connection by soldering can be maintained for a long term between the wiring board and an outer electric circuit board, such as printed board. SOLUTION: A ceramic wiring board A is provided with multiple connecting terminals 4. An outer electric circuit board B is made of wiring conductor, formed and adhered to the surface of an insulator-containing organic resin. The ceramic wiring board A is placed on the outer electric circuit board B and wiring terminals 4 of the wiring board A and wiring conductor 11 are soldered to form a mounting structure for a wiring board. In this structure, the value of F=L×Δα/H<2> is 2000 or less. In the formula, L is the maximum spacing distance between two of multiple-connecting terminals mounted on the insulating board (mm). Δα is the difference in coefficient of thermal expansion at 40-400 deg.C between the insulating board and the outer electric circuit board in the wiring board (ppm/ deg.C). H is the height of solder between the wiring board and the outer electric circuit board (mm).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for mounting a wiring board, particularly a large surface-mounting wiring board, on the surface of an external electric circuit board provided with an insulator containing an organic resin by brazing. The mounting structure.

[0002]

2. Description of the Related Art Conventionally, a wiring board has a structure in which a metallized wiring layer is disposed on the surface or inside of an insulating substrate.
Also, typical examples of the wiring board include a semiconductor element,
In particular, a semiconductor device housing package for housing a semiconductor integrated circuit device such as an LSI (Large Scale Integrated Circuit Device)
A concave portion for accommodating semiconductor elements is formed on the surface of an insulating substrate generally made of alumina ceramics, and a plurality of metallized wiring layers made of a refractory metal powder such as tungsten and molybdenum are formed on the surface and inside of the insulating substrate. It is provided and is electrically connected to the semiconductor element housed in the recess. In addition, a connection terminal for electrically connecting to an external electric circuit board is provided on a lower surface or a side surface of the insulating substrate, and the connection terminal is electrically connected to the metallized wiring layer.

In such a package for housing a semiconductor element, connection terminals provided on the lower surface or side surfaces of the insulating substrate and wiring conductors formed on the surface of the external electric circuit board are electrically connected by soldering or the like. It is implemented by

In general, as the degree of integration of a semiconductor device increases, the number of electrodes formed on the semiconductor device also increases. As a result, the number of terminals in a semiconductor housing package for housing the same increases. However, as the number of electrodes increases, it is necessary to increase the dimensions of the package itself. At the same time, it is also required to reduce the size, so that the density of connection terminals in the package needs to be increased.

The structure of connection terminals in a conventional package is most commonly a pin grid array (PGA) in which metal pins such as Kovar are connected to the lower surface of the package. A quad flat package (QFP) in which an L-shaped metal member is brazed to a metallized wiring layer led out to the side, a leadless chip carrier (LC) without lead pins having electrode pads on four sides of the package
C) Further, there is a ball grid array (BGA) constituted by spherical terminals made of solder on the lower surface of the insulating substrate. Among them, it is said that the BGA can achieve the highest density.

In this ball grid array (BGA), connection terminals are constituted by terminals in which spherical terminals made of a brazing material such as solder are soldered to connection pads, and the spherical terminals are mounted on wiring conductors of an external electric circuit board. After that, the terminals are heated and melted at a temperature of about 250 to 400 ° C., and the spherical terminals are bonded to a wiring conductor to be mounted on an external electric circuit board. With such a mounting structure, each electrode of the semiconductor element housed in the semiconductor element housing package is electrically connected to an external electric circuit via the metallized wiring layer and the connection terminal.

Further, recently, as an insulating substrate in a package for housing a semiconductor element, a glass ceramic sintered body is used as an insulating substrate because copper wiring having a low temperature firing, a low dielectric constant, and a high electric conductivity is possible. Configurations have also been proposed.

[0008]

Alumina conventionally used as an insulating substrate in the above package,
Ceramics such as mullite have a high strength of 200 MPa or more and are often used as a multi-layer technology with metallized wiring layers because of their high reliability, but the insulating substrate is made of glass-epoxy resin composite material, glass- When surface mounted on an external electric circuit board such as a printed circuit board containing an organic resin such as a polyimide resin composite material, when heat generated during operation of the semiconductor element is repeatedly applied to both the insulating substrate and the external electric circuit board, the external Since the difference in thermal expansion coefficient between the electric circuit board and the insulating substrate is as large as 10 ppm / ° C. or more, there is a problem that thermal stress is generated.

This thermal stress is relatively small when the number of terminals in the package is relatively small, less than 300, or when the connection terminals are composed of pins or when the size of the package itself is small. However, when the number of connection terminals becomes 300 or more, or when the package size is increased, the generated stress tends to increase, and this is repeated on the solder mounting portion of the package on the external electric circuit board by the operation / stop of the semiconductor element. When this voltage is applied, stress concentrates on the outer peripheral portion of the connection terminal of the package and on the joint interface between the wiring conductor of the external electric circuit board and the connection terminal. It has a fatal disadvantage that it is separated from the wiring conductor of the electric circuit board and the connection terminal of the package cannot be stably electrically connected to the wiring conductor of the external electrode circuit for a long period of time. In particular, the above tendency is remarkable in the surface mount type packages such as the QFP, LCC and BGA types.

Accordingly, the present invention provides a stable and stable circuit board for a long period of time when a wiring board such as a package for housing a semiconductor element is surface-mounted by brazing to an external electric circuit board whose insulator is mainly composed of an organic resin. It is an object of the present invention to provide a highly reliable wiring board mounting structure capable of maintaining a connection state.

[0011]

Means for Solving the Problems The present inventors have conducted various studies on a method of alleviating the thermal stress generated when a wiring board such as a package is mounted on an external electric circuit board. Stress generated in the solder by controlling the length, the brazing height between the insulating board of the wiring board and the external electric circuit, and the thermal expansion difference between the wiring board and the external electric circuit so as to have a specific relationship And found that stable mounting can be performed over a long period of time, leading to the present invention.

That is, the mounting structure of the wiring board according to the present invention comprises a ceramic insulating substrate, a metallized wiring layer provided on the insulating substrate, and a metallized wiring layer attached to the insulating substrate and electrically connected to the metallized wiring layer. A wiring board having a connection terminal and an external electric circuit board on which a wiring conductor is adhered and formed on an insulator containing at least an organic resin. A mounting structure of a wiring board, wherein the wiring conductor of the board is soldered and mounted.

[0013]

(Equation 1)

The F value represented by the formula is 2,000 or less.

In particular, the maximum separation distance between connection terminals on the wiring board is 6 mm or more, and the coefficient of thermal expansion of the insulating substrate at 40 to 400 ° C. is 8 to 25 ppm /
℃, 40-400 ℃ of the external electric circuit board
Is preferably from 8 to 28 ppm / ° C.

As the insulating substrate, in particular, the insulating substrate in the wiring substrate is formed of a glass ceramic sintered body, specifically, lithium silicate glass containing Li ₂ O in an amount of 5 to 30% by weight. % By volume and at least one of forsterite, cristobalite and quartz
It is desirable that the mixture be made of a mixture comprising 80 to 20% by volume of a filler containing seeds and fired.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings showing an embodiment. FIGS. 1 and 2 are views showing an example of the present invention, which is based on a so-called wiring board having a metallized wiring layer disposed on the surface or inside of a ceramic insulating substrate, and FIG. 1 shows a BGA type package and its mounting structure as an example of a wiring board in the present invention, wherein A is a BGA type package, and B is an external electric circuit board.

In FIG. 1, a package A includes a ceramic insulating substrate 1, a lid 2, a metallized wiring layer 3, connection terminals 4, and a semiconductor element 5 housed inside the package. The semiconductor element 5 is housed in the cavity 6, and the cavity 6 is hermetically sealed by the lid 2.

A connection terminal 4 is formed on the lower surface of the insulating substrate 1 and is electrically connected to the metallized wiring layer 3 disposed on the surface and inside of the insulating substrate 1. This figure 1
In the BGA type package, the connection terminals 4 are formed, for example, by a large number of electrode pads 7 formed on the lower surface of the insulating substrate 1.
And a ball-shaped terminal 8 made of a high melting point brazing material such as solder (tin-lead alloy).

On the other hand, the external electric circuit board B is made of a so-called printed board, and is made of glass-epoxy resin, glass-
Cu, Au, Al, Ni, P on the surface of the insulator 10 made of a material containing an organic resin such as a polyimide resin composite material.
The wiring conductor 11 made of a metal such as b-Sn is adhered and formed, and may hereinafter be simply referred to as a printed circuit board.

To mount the BGA type package A on the printed circuit board B, the ball-shaped connection terminals 8 on the lower surface of the insulating substrate 1 of the package A are connected to the wiring conductors 11 of the printed circuit board B.
It is mounted on the printed circuit board B with a brazing material 12 such as low melting point solder.

According to the present invention, in the mounting structure as shown in FIG. 1, two connection terminals out of the plurality of connection terminals attached to the insulating substrate of the wiring board A such as a package for housing semiconductor elements. L (mm), the difference in thermal expansion coefficient between the insulating substrate 1 and the external electric circuit board B in the wiring board A is Δα (ppm / ° C.), and the solder between the insulating substrate 1 and the external electric circuit board B When the mounting height is H (mm),

[0023]

(Equation 1)

It is important that the F value represented by the following is not more than 2000.

Here, the maximum separation distance L between two connection terminals is defined as the separation distance between one connection terminal and another connection terminal among a plurality of connection terminals attached to the insulating substrate of the wiring board. The maximum value is, for example, the separation distance between the connection terminal attached to one end of the connection terminal group and the connection terminal attached to the other end. More specifically, FIG. As shown in (a), when the connection terminal group is arranged in a square shape, it corresponds to the diagonal length of the square shape. FIG.
When arranged in a complicated shape as shown in (b),
As shown in FIG. 2B, the farthest distance between terminals corresponds.

As shown in the enlarged view of the mounting portion in FIG. 3, the brazing height H is the wiring conductor on the surface of the external electric circuit board B in the mounting structure of the wiring board in FIG. 1
1 to the surface of the electrode pad 7 on the wiring board A. (B) shows another connection terminal structure. According to (b), the recess 13 is formed on the lower surface of the wiring board A, the electrode pad 7 is formed in the recess 13, and the ball-shaped terminal 8 is provided in the recess 13. In this case, the brazing height H is determined from the surface of the wiring conductor 11 on the surface of the external electric circuit board B to the wiring board A.
To the bottom surface of the insulating substrate 1. In the above configurations (a) and (b), the same concept is applied to a case where the ball-shaped terminal 8 is mounted without using the brazing material alone or a case where a pillar-shaped terminal or the like is used instead of the ball-shaped terminal 8. The brazing height H is determined.

The stress generated between the insulating board 1 of the wiring board A and the external electric circuit board B is expressed by the following equation (1).
The larger the maximum length L of the wiring board and the difference in thermal expansion coefficient Δα between the two, the larger it becomes. This is because, when the difference between the maximum length and the thermal expansion coefficient increases, the difference in thermal expansion or contraction between the insulating substrate 1 and the external electric circuit board B increases due to a temperature change.

However, the insulating substrate 1 and the external electric circuit board B
By increasing the brazing height H, the stress can be reduced. That is, even if the maximum length L of the insulating substrate 1 and the thermal expansion coefficient difference Δα between the insulating substrate and the external electric circuit board are large to some extent, reliability can be obtained by adjusting the brazing height between the two. It is. Equation (1) derives a relationship for obtaining high reliability based on the elements.

Therefore, if the maximum length L of the wiring board, the difference in thermal expansion coefficient Δα between the wiring board and the external electric circuit board, and the brazing height H between the insulating board and the external electric circuit board do not satisfy the range of the above formula, As a result, the stress acting on the attachment portion increases, and it becomes impossible to prevent the electrical connection state from deteriorating with time.

In particular, according to the mounting structure of the present invention, it is desirable that the F value represented by the above equation 1 is 1000 or less, more preferably 500 or less. In addition, the maximum separation distance between the connection terminals at which the influence of the stress due to the difference in thermal expansion becomes large is 6 mm.
As described above, in particular, a wiring board having a length of 10 mm or more, and more preferably a length of 12 mm or more, has a thermal expansion coefficient of 8 to 28 p at 40 to 400 ° C.
It is suitable for mounting on an external electric circuit board at pm / ° C.

According to a preferred aspect of the present invention, the ceramic insulating substrate of the wiring board has a thermal expansion coefficient of 8 to 25 ppm / ° C. at 40 to 400 ° C. and an absolute value of a thermal expansion difference Δα from an external electric circuit board. And the soldering height H of the wiring board to the external electric circuit board.
Is desirably 0.1 to 1.2 mm. this is,
When the difference in thermal expansion coefficient is large, the generated stress is highly dependent on the brazing height, so that fine adjustment of the brazing height is required, whereas the thermal expansion coefficient difference is reduced. Thereby, since the generated stress can be reduced, the allowable range of the brazing height can be expanded in controlling the F value within the range. If the brazing height H deviates from the above range, mounting failures such as disconnection and short-circuit between solders are likely to occur at the brazing portion.

As a method of adjusting the brazing height H, the mounting height of the brazing material 9 when brazing the ball-shaped terminals 8 to the electrode pads 7 in FIG. A method of installing and adjusting a spacer having an appropriate height when mounting the semiconductor device and an external electric circuit board, and a method of adjusting the size (for example, a ball diameter) of the ball-shaped terminals 8 and the column-shaped terminals can be adopted.

As a preferable insulating material for forming the ceramic insulating substrate in the wiring board, Al ₂ O ₃ , AlN, Zr as long as the F value satisfies the above range.
Known insulating materials such as ceramics mainly composed of O ₂ , mullite, Si ₃ N ₄ , and SiC, glass, and glass ceramics can be used.

Among these, the metallized wiring layer disposed on the surface and inside is made of at least one of gold, copper, and silver, and can be manufactured by simultaneous firing with the insulating substrate. It is desirable.
From this point, it is desired that the insulating substrate can be fired at 1000 ° C. or lower, and for example, glass or glass ceramics that can be fired at 1000 ° C. or lower is most preferable.

Examples of the glass or glass ceramic include borosilicate glass and soda-lime glass and the like, and Al ₂ O ₃ as a filler component in these glasses.
Glass ceramics containing O ₃ , ZrO ₂ , SiO ₂ , MgO, CaO, AlN, and the like are included.

Further, as such an insulating substrate, 40 to 400
As a glass ceramic material having a thermal expansion coefficient of 8 to 25 ppm / ° C. at 20 ° C., 20 to 80% by volume of a crystalline lithium silicate glass containing 5 to 30% by weight of Li ₂ O;
A glass ceramic sintered body obtained by molding and firing a mixture comprising at least 80 to 20% by volume of a filler component containing at least forsterite and cristobalite is preferably used.

According to the present invention, by blending the crystalline lithium silicate glass in the above range, it can be fired at a temperature of 1000 ° C. or less, and the sintered body after sintering has a Young's modulus of 200%.
A glass ceramic having GPa or less and a thermal expansion coefficient of 8 ppm / ° C. or more can be obtained.

The glass ceramic material will be specifically described below. As the crystalline lithium silicate glass to be used, Li ₂ O is contained at a ratio of 5 to 30% by weight, SiO ₂ is contained at a ratio of 60 to 85% by weight, and Li ₂ O is used.
And the total amount of SiO ₂ is 65 to 95% by weight, and the balance is A
l ₂ O ₃ , alkaline earth oxides, alkali metal oxides,
Those composed of ZnO, P ₂ O _{5 and the} like are preferable.

The softening point of the crystalline lithium silicate glass is desirably 420 to 460 ° C. Further, the yield point is desirably 400 ° C. to 800 ° C., particularly preferably 400 ° C. to 650 ° C., in order to efficiently remove the molding organic binder and to enhance co-sintering with copper.

On the other hand, it is preferable to include at least forsterite and cristobalite as the filler component blended with the crystalline lithium silicate glass in order to control the thermal expansion coefficient within the above range. It is also possible to control the Young's modulus and the coefficient of thermal expansion depending on the type of filler, and as other filler components, quartz (SiO ₂ ), tridymite (SiO ₂ ), cristobalite (SiO ₂ ), forsterite ( 2MgO ・
SiO _2), spinel _{(MgO · Al 2 O 3)} , wollastonite (CaO · SiO _2), Monty Sera Knight _{(CaO · MgO · SiO 2)} , nepheline (Na ₂ O
・ Al ₂ O ₃ .SiO ₂ ), lithium silicate (Li
₂ O.SiO ₂ ), diopside (CaO.MgO.2)
SiO ₂ ), melvinite (3CaO.MgO.2Si)
O ₂ ), Akermite (2CaO.MgO.2Si)
O ₂ ), magnesia (MgO), alumina (Al
₂ O _3), Kanegiaito _{(Na 2 O · Al 2 O} 3 · 2
SiO ₂ ), enstatite (MgO.SiO ₂ ), magnesium borate (2MgO.B ₂ O ₃ ), celsian (BaO.Al ₂ O ₃ .2SiO ₂ ), B ₂ O ₃ .2M
gO.2SiO ₂ , garnite (ZnO.Al
₂ O ₃ ) and petalite (LiAlSi ₄ O ₁₀ ).

In order to prepare a wiring board using the mixture of the crystalline glass and the filler, an appropriate molding organic resin binder is added, and then a desired molding means, for example,
It is formed into a sheet by a doctor blade, a rolling method, a mold press or the like.

Then, a metallizing paste such as copper or gold is printed on the surface of the sheet-like molded body by a screen printing method or the like, and in some cases, the green sheet is appropriately punched to form through holes. This hole is also filled with a metallizing paste. Then, a plurality of these green sheets are laminated and fired.

In firing, first, the binder component blended for molding is removed.

The removal of the binder is performed in an air atmosphere at about 700 ° C. When Cu is used as the wiring conductor, the removal is performed in a nitrogen atmosphere containing water vapor at 100 to 700 ° C. At this time, the shrinkage start temperature of the molded body is 70
It is desirable that the temperature is about 0 to 850 ° C., and if the shrinkage onset temperature is lower than this, it is difficult to remove the binder. Is required.

The calcination is performed in an oxidizing atmosphere at 850 ° C. to 1050 ° C., whereby the relative density is increased to 90% or more. If the firing temperature at this time is lower than 850 ° C., densification cannot be achieved, and if it exceeds 1050 ° C., the metallized layer is melted by simultaneous firing with the metallized wiring layer.

The glass-ceramic sintered body constituting the insulating substrate of the wiring board thus manufactured contains a crystalline phase such as forsterite or cristobalite added as a filler or an enstatite or the like based on these filler components. There is a crystal phase and further a lithium silicate crystal phase precipitated from the crystalline glass. In addition, there may be a crystal phase generated by the reaction between the crystalline glass and the filler. Then, a small amount of a glass phase may be present at the grain boundaries of these crystal phases. By precipitating a crystal phase having a large thermal expansion coefficient, a glass ceramic sintered body having a high thermal expansion coefficient can be produced.

According to the present invention, as described above,
In the mounting structure of a wiring board for an external electric circuit composed of a printed board such as an epoxy resin board, the stress generated between the wiring board and the external electric circuit board is reduced, and as a result, the connection terminals of the wiring board and the external electric circuit due to the stress are reduced. It is possible to prevent the occurrence of a connection failure with the wiring conductor of the circuit, whereby, for example, the semiconductor element housed in the package and the external electric circuit board are accurately and firmly electrically connected for a long period of time. It is possible to do.

[0048]

【Example】

Example 1 Various ceramic materials for forming the insulating substrates shown in Tables 1 and 2 were fired under the firing conditions in Tables 1 and 2 to obtain 5 × 4 × 40.
mm sintered body was prepared, and for each sintered body, 40 to
The thermal expansion coefficients at 400 ° C. were measured and are shown in Tables 1 and 2.

Also, using various ceramic materials shown in Tables 1 and 2, a paste containing a metallized metal made of the materials shown in Tables 1 and 2 is applied, and a through hole is formed. A connection pad made of Cu or W metallization was formed at the place to be connected, and simultaneously baked together with the metallized wiring layer, through hole and electrode pad under the conditions shown in Tables 1 and 2, to produce a wiring board. Then, after the connection pads are plated with Ni, a high melting point solder (Pb 90% by weight-Sn 10% by weight) is applied to the electrode pads.
Ball-shaped connection terminals made of low melting point solder (Pb 40% by weight-Sn 60% by weight). The connection terminals were formed on the entire lower surface at a density of 30 terminals per 1 cm ² as shown in FIG. Also, 116 terminals having a maximum separation distance of 16 mm at the connection terminals, and 71 m
A wiring board to which m 732 terminals were attached was fabricated. In addition, the thickness of all the wiring boards was 1.6 mm.

On the other hand, as an external electric circuit board, glass
A printed circuit board was prepared in which a wiring conductor made of copper foil was formed on the surface of an insulator made of an epoxy substrate having a thermal expansion coefficient of 13 ppm / ° C. at 40 to 400 ° C.

Then, the wiring board is aligned so that the wiring conductors on the printed board and the connection terminals of the package insulating board are connected, and the wiring board is mounted on the printed board surface using the low melting point solder. Implemented. The brazing height H at this time was adjusted by changing the mounting height of the ball-shaped terminals to the electrode pads by soldering and by changing the diameter of the ball made of high melting point solder.

(Thermal Cycle Test) Next, the test sample obtained by mounting the package substrate on the surface of the printed circuit board as described above was placed in a thermostat controlled at -40 ° C. and 125 ° C. in the atmosphere of the air. Up to 1000 cycles were repeated with 15 minutes / 15 minutes holding as one cycle.

The electrical resistance between the wiring conductor of the printed circuit board and the package substrate was measured for each cycle, and the number of cycles until the electrical resistance changed was shown in Tables 1 and 2.

[0054]

[Table 1]

[0055]

[Table 2]

As is clear from Tables 1 and 2, the maximum length L of the insulating substrate, the difference in thermal expansion coefficient Δα from the external electric circuit board,
Samples having an F value of 2000 or less related by the brazing height H between the insulating substrate and the external electric circuit board are all 10 samples.
No change in resistance was observed at all until the 00th cycle, and an extremely stable and favorable electrical connection state could be maintained. However, in a sample having an F value smaller than 2,000, a change in resistance was detected in less than 1,000 cycles, and it was found that reliability after mounting was lacking.

Example 2 As a glass ceramic sintered body, as shown in Table 3, lithium silicate glass (composition: 74 wt% SiO ₂ , 14 wt% Li ₂ O, 4 wt% Al ₂ O ₃ , 2 wt% K ₂ O,
2% by weight P ₂ O ₅ , 2% by weight Na ₂ O, 2% by weight Zn
O, a thermal expansion coefficient at a deformation point of 480 ° C. and 40 to 400 ° C., and a volume ratio of alumina were changed and mixed, molded in the same manner as in Example 1, debindered, and fired. Then, the thermal expansion coefficient of the sintered body obtained as described above was confirmed in the same manner as in Example 1.

Further, a wiring board was prepared by using Cu as the metallized wiring layer in the same manner as in Example 1, mounted on the same glass-epoxy substrate as in Example 1, and subjected to a thermal cycle test during mounting, followed by printing. The change in electrical resistance between the substrate and the package substrate was examined.

[0059]

[Table 3]

As is clear from Table 3, the maximum length L of the insulating substrate, the difference in thermal expansion coefficient Δα from the external electric circuit board, and the brazing height H between the insulating substrate and the external electric circuit board were related. Samples with an F value of 2000 or less were all 1000
No change in resistance was observed at all until the cycle, and an extremely stable and good electrical connection state could be maintained. However, if the F value is 2
In a sample smaller than 000, a change in electric resistance due to breakage of the connection portion was observed in less than 1000 cycles.

Example 3 As shown in Tables 4 and 5, lithium silicate glass (composition: 78
Wt% SiO ₂ , 10 wt% Li ₂ O, 4 wt% Al ₂
O ₃ , 4% by weight K ₂ O, 2% by weight P ₂ O ₅ , 2% by weight N
a ₂ O, yield point 480 ° C., the thermal expansion coefficient 10.3 ppm / ° C.) at 40 to 400 ° C., forsterite as a filler, using cristobalite, petalite, nepheline, lithium silicate, Tables 4 and 5 and their filler , And molded in the same manner as in Example 1, debinding treatment and firing. The Young's modulus and the coefficient of thermal expansion of the obtained sintered body were confirmed in the same manner as in Example 1.

After a green sheet is formed in the same manner as in Example 1, a Cu metallizing paste is applied to the wiring pattern by a screen printing method, and a through hole is formed at a predetermined portion of the sheet to pass through to the lower surface of the substrate. Was also filled with Cu metallized paste. And Example 1
In the same manner as described above, this green sheet is laminated and pressed and fired to prepare a wiring board for a package. The wiring board for the package is mounted on the surface of a printed circuit board, and subjected to a thermal cycle test in the same manner as in Example 1. Up to 1000 cycles were performed.

[0063]

[Table 4]

[0064]

[Table 5]

As is clear from Tables 4 and 5, the maximum length L of the insulating substrate, the difference in thermal expansion coefficient Δα from the external electric circuit board,
Samples having an F value of 2000 or less associated with the brazing height H between the insulating substrate and the external electric circuit board are all 10 samples.
No change in resistance was observed at all until the 00th cycle, and an extremely stable and favorable electrical connection state could be maintained. However, in a sample having an F value smaller than 2,000, a change in resistance was detected in less than 1,000 cycles, and it was found that reliability after mounting was lacking.

[0066]

As described in detail above, according to the mounting structure of the wiring board of the present invention, when a large ceramic wiring board is mounted on an external electric circuit board such as a printed board having a large thermal expansion coefficient, both of them can be used. Stress due to the difference in thermal expansion coefficient between the wiring board and the external electric circuit can be accurately and firmly electrically connected for a long period of time. It is possible to realize a highly reliable wiring board mounting structure capable of sufficiently supporting terminals.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a mounting structure of a ball grid array type semiconductor element storage package according to the present invention.

FIG. 2 is a diagram for explaining a maximum separation distance L between connection terminals according to the present invention.

FIG. 3 is an enlarged view of a mounting unit according to the present invention, and FIG.
Is a mounting part of the package of FIG. 1, and (b) is a mounting part in another connection terminal structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ceramic insulating substrate 2 Lid 3 Metallized wiring layer 4 Connection terminal 5 Semiconductor element 6 Cavity 7 Electrode pad 8 Ball-shaped terminal 9 Low melting point solder 10 Insulator 11 Wiring conductor 12 Brazing material 13 Depression A Wiring board B External electric circuit board

──────────────────────────────────────────────────の Continuing on the front page (51) Int.Cl. ⁶ Identification code FI H05K 3/36 (72) Inventor Hitoshi Kumadahara 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima Inside the Kyocera Research Institute (72) Inventor Kenichi Nagae 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima Inside the Kyocera Research Institute

Claims (6)

[Claims] 1. A wiring comprising a ceramic insulating substrate, a metallized wiring layer disposed on the insulating substrate, and a plurality of connection terminals attached to the insulating substrate and electrically connected to the metallized wiring layer. The substrate is placed on an external electric circuit board on which a wiring conductor is attached and formed on the surface of an insulator containing at least an organic resin, and the connection terminals of the wiring board and the wiring conductor of the external electric circuit board are brazed. In the mounting structure of the wiring board which is mounted by mounting, A mounting structure of a wiring board, wherein the F value represented by is 2000 or less. 2. The wiring board according to claim 1, wherein the maximum separation distance of the connection terminals is 6 mm or more.
The mounting structure of the wiring board described. 3. The mounting structure according to claim 1, wherein the thermal expansion coefficient of the insulating substrate at 40 to 400 ° C. is 8 to 25 ppm / ° C. 4. The mounting structure according to claim 3, wherein said insulating substrate is made of a sintered glass ceramic. 5. The mounting structure according to claim 1, wherein the external electric circuit board has a coefficient of thermal expansion at 40 to 400 ° C. of 8 to 28 ppm / ° C. 6. The insulating substrate according to claim 1, wherein said insulating substrate comprises 20 to 80% by volume of lithium silicate glass containing 5 to 30% by weight of Li ₂ O, and 80 to 20% by volume of a filler containing at least one of forsterite, cristobalite and quartz. 5. The mounting structure for a wiring board according to claim 4, wherein the mixture is formed by molding and firing.