JP2992441B2 - Prepreg and laminated board, multilayer printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prepreg based on glass cloth and a laminate using the prepreg.
The present invention relates to a printed wiring board.

[0002]

2. Description of the Related Art In recent years, printed wiring boards have been rapidly becoming multi-layered, thinner and denser in insulating layers, as electronic devices have become more sophisticated, lighter and thinner. For this reason, there is a strong demand for a material constituting the printed wiring board to have improved quality such as heat resistance to moisture absorption, high dimensional stability, and long-term insulation reliability.

As a prepreg constituting a printed wiring board as described above, a prepreg prepared by impregnating a glass cloth with a varnish of a thermosetting resin and drying is generally used. Then, a plurality of prepregs are laminated, and a metal foil is laminated as necessary, and the laminate is formed by heating and pressing. Further, a printed wiring board can be finished by forming a circuit by printing the metal foil of the laminated board. Furthermore, a printed wiring board is used as an inner circuit board, and a prepreg is superimposed on this surface, and a metal foil is further superimposed on the outside, and this is heated and pressed to form a multilayer board. By forming a circuit by printing or the like of the metal foil described above, a multilayer printed wiring board can be finished.

FIG. 3A shows a cross section of a multilayer printed wiring board A. In the figure, reference numeral 1 denotes an inner layer circuit board provided with an inner layer circuit 2 on the surface, and a glass cloth 4 constituted by a glass cloth yarn 3 is laminated on the surface thereof via a layer of a thermosetting resin 5. And this multilayer printed wiring board A
When a thermal shock acts on the glass cloth 4, thermal stress is generated in the direction of the arrow x along the interface between the glass cloth 4 and the layer of the thermosetting resin 5. This stress is divided into a vector in the thickness direction (y arrow) and a vector in the plane direction (z arrow) of the multilayer printed wiring board A, and the stress of the glass cloth 4 of the glass cloth yarn 3 constituting the warp and the weft of the glass cloth 4. The greater the curvature of the bend (waveform) in the thickness direction, the greater the component force in the thickness direction (y arrow) of the glass cloth 4 having a high elastic modulus, and the greater the force between the glass cloth 4 and the layer of the thermosetting resin 5. And peeling easily occurs.

[0005] The same applies to the laminate B. That is, FIG. 4A shows a cross section of the laminate B. The laminated plate B is formed by laminating a glass cloth 4 composed of glass cloth yarns 3 via a layer of a thermosetting resin 5. A thermal stress is generated in the direction of the arrow x along the interface between the layer of the thermosetting resin 5 and the stress is divided into a vector in the thickness direction (y arrow) and a plane direction (z arrow) of the laminate B. As the curvature (waveform) of the glass cloth 4 constituting the warp or weft of the glass cloth 4 in the thickness direction of the glass cloth 4 increases, the thickness direction (y of the glass cloth 4 having a higher elastic modulus increases. Component force to the arrow (arrow) increases, and peeling between the glass cloth 4 and the layer of the thermosetting resin 5 easily occurs.

FIG. 3B shows the cross section of the glass cloth 4 of the multilayer printed wiring board A and the distribution of the density of the glass components. The warp yarn 6 and the weft yarn composed of the glass cloth yarn 3 of the glass cloth 4 are shown in FIG. At the intersection of 7, the glass component becomes dense and the component of the thermosetting resin 5 becomes poor. Between the intersections of the warp 6 and the weft 7, the glass component becomes sparse and the component of the thermosetting resin 5 becomes rich. Become. And, as the number of intersections between the warp 6 and the weft 7 per predetermined area increases, the interval between the intersections of the warp 6 and the weft 7 decreases, the interval between the coarseness and denseness of the glass component decreases, and the coarseness of the glass component decreases. The pitch of the density change becomes smaller. The cross-sectional shape of the glass cloth yarn 3 constituting the warp yarn 6 and the weft yarn 7 is generally elliptical,
When the difference between the minor axis a and the major axis b is an elliptical cross section, the difference between the sparseness and the denseness of the glass component increases. Since the resin has a larger coefficient of thermal expansion than the resin, if the difference between the coarseness and the fineness of the glass component is large, and if the pitch of the change in the coarseness and the fineness of the glass component is small, the thermal shock is applied to the multilayer printed wiring board A. When acting, the strain stress generated between the glass cloth 4 and the layer of the thermosetting resin 5 increases due to the difference in the coefficient of thermal expansion between the resin and the glass. Peeling easily occurs between the layers.

This is the same for the laminate B as shown in FIG.

[0008]

As described above, the performance of the thermal shock depends on the waveform pitch of the glass cloth yarn of the glass cloth, the interval between the intersection points of the warp and weft yarns, the cross-sectional shape of the glass cloth yarn, and the like. It is expected that
Therefore, a conventionally used glass cloth was observed from the surface, the number of intersections of the warp 6 and the weft 7 per 1 cm ² was measured, and the overlapping area at one intersection of the warp and the weft was measured. In addition, by observing the cross section in the thickness direction of a conventionally used glass cloth, the period p of the waveform of the glass cloth yarn is measured, and the ratio a / b of the short diameter a to the long diameter b of the cross-sectional shape of the glass cloth yarn is measured. Was measured. Table 1 shows the results.

[0009]

[Table 1]

[0010] The conventional glass cloth is as shown in Table 1 and has poor surface smoothness, which is expected to have a problem in heat resistance such as thermal shock resistance. The present invention has been made in view of the above points, and an object of the present invention is to provide a prepreg, a laminate, and a multilayer printed wiring board that can improve heat resistance.

[0011]

The present invention relates to a prepreg made by impregnating and drying a thermosetting resin in a glass cloth, and assuming that the glass cloth has a thickness of X μm, the warp and the weft of the glass cloth are formed. Assuming that the number of intersections per 1 cm ² is (130−X / 2) to (230−X / 2) / cm ² and that the thickness is X μm, the warp and the weft
Overlapping area in one intersection, X / 300 mm ² or more
The glass cloth that is above and composes warp and weft yarns
The yarn has a substantially elliptical shape that is flat in the thickness direction of the glass cloth.
It has a cross-sectional shape, and the ratio of the minor axis a to the major axis b of the ellipse
(A / b) is 0.1 or less and the thickness is 17
In the case of a glass cloth of 0 μm or less,
Waveform of glass cloth yarn appearing in cross section in thickness direction
With a period of 1.2 mm or more is used.
It is characterized by the following.

[0012] The present invention also relates to a thermosetting resin for a glass cloth.
In the pre-preg that is created by impregnation and drying the fat, as a glass cloth, when the thickness thereof Xmyuemu, glass
Assuming that the number of intersections per 1 cm ² between the warp and the weft of the cloth is (130−X / 2) to (230−X / 2) / cm ² and that the thickness is X μm, the warp and the weft are
Overlapping area in one intersection, X / 300 mm ² or more
The glass cloth that is above and composes warp and weft yarns
The yarn has a substantially elliptical shape that is flat in the thickness direction of the glass cloth.
It has a cross-sectional shape, and the ratio of the minor axis a to the major axis b of the ellipse
(A / b) is 0.1 or less and the thickness is 17
In the case of glass cloth exceeding 0 μm, use glass cloth
Of glass cloth yarn appearing on the cross section in the thickness direction
Shapes with a period of 1.8 mm or more are used
It is characterized by the following.

[0013]

Further, the present invention relates to a laminated plate characterized by using the above prepreg. Furthermore, the present invention relates to a multilayer printed wiring board characterized by using the above prepreg. Less than,
The present invention will be described in detail.

The glass cloth 4 is formed by weaving the warp yarns 6 and the weft yarns 7 composed of the glass cloth yarns 3 in an intersecting manner. In the present invention, the glass cloth 4 having a super smooth surface is used. In order to develop, first, the interval between the intersections of the warp yarn 6 and the weft yarn 7 is regulated. That is, when the thickness of the glass cloth 4 is X μm, the number of intersections per 1 cm ² between the warp yarn 6 and the weft yarn 7 of the glass cloth 4 is (130−X / 2) pieces / cm ² to (230−X / 2) The glass cloth 4 is prepared so as to be in the range of pieces / cm ² . Warp 6
If the number of intersections between the warp 6 and the weft 7 exceeds (230-X / 2) pieces / cm ² , the interval between the warp 6 and the weft 7 is short and the glass cloth 4 of the glass cloth yarn 3 constituting the warp 6 and the weft 7 The curvature of the bend (waveform) in the cross section increases. In order to make the surface of the glass cloth 4 ultra-smooth by reducing the curvature of the bend (waveform) of the glass cloth yarn 3, the warp yarn 6 and the weft yarn 7
Must be less than (230−X / 2) / cm ² . However, the number of intersections between the warp yarn 6 and the weft yarn 7 is (1
When it is less than 30-X / 2) pieces / cm ² , the cloth structure becomes too sparse, causing a problem in strength and a problem in that a problem may also occur in resin impregnation.
The number of intersections between the warp yarn 6 and the weft yarn 7 is (130-X / 2) / c
m ² or more. Here, the thickness X of the glass cloth 4 is not particularly limited, but generally the lower limit is 25 μm and the upper limit is 250 μm.

Further, the bending (waveform) of the glass cloth yarn 3 constituting the warp yarn 6 and the weft yarn 7 in the cross section of the glass cloth 4.
In order to reduce the curvature, the period of the waveform of the glass cloth yarn 3 is increased. The period p of the waveform of the glass cloth yarn 3, that is, the interval from the peak (or valley) of the waveform to the peak (or valley) is determined by the interval between three warp yarns 6 and the weft yarn 7.
However, if the period p is small, the curvature of the waveform becomes large and the surface of the glass cloth 4 cannot be adjusted to be super-smooth. For this reason, in the present invention, in the case of the glass cloth 4 having a thickness of 170 μm or less, the period p of the waveform of the glass cloth yarn 3 is 1.2 mm.
In the case of using a glass cloth 4 having a thickness of more than 170 μm, a glass cloth yarn 3 having a waveform period p of 1.8 mm or more is used. Although the upper limit of the period p of the waveform of the glass cloth yarn 3 is not particularly set, it is naturally regulated by the setting of the number of intersections between the warp yarn 6 and the weft yarn 7.

Further, in order to adjust the surface of the glass cloth 4 to be ultra-smooth, the cross-sectional shape of the glass cloth yarn 3 constituting the warp yarn 6 and the weft yarn 7 needs to be as flat as possible. And glass cloth yarn 3 is glass cloth 4
Has a flattened elliptical cross-sectional shape in the thickness direction. In the present invention, the ratio (a / b) of the minor axis a to the major axis b (a / b) is 0.1 or less. A glass cloth 4 is used. The ratio of minor axis a to major axis b (a
With glass cloth yarn 3 where / b) exceeds 0.1, ultra-smooth glass cloth 4 cannot be obtained. No upper limit is set.

If the cross-sectional shape of the glass cloth yarn 3 is flat, the area where the warp yarn 6 and the weft yarn 7 overlap at the intersection becomes large. Therefore, in the present invention, assuming that the thickness of the glass cloth 4 is X μm, the overlapping area at one intersection between the warp yarn 6 and the weft yarn 7 is X / 300 mm.
And to use the ² or more. No upper limit is set.

A prepreg can be prepared by using a glass cloth prepared so as to satisfy the above conditions, impregnating the glass cloth with a varnish such as an epoxy resin, a phenol resin, or a polyimide resin and drying by heating. . And a laminated board can be manufactured using this prepreg. That is, a laminated board can be prepared by laminating a plurality of prepregs, laminating metal foils such as copper foils as necessary, and forming the laminate by heating and pressing. Further, a printed wiring board can be finished by forming a circuit by printing the metal foil of the laminated board.

Furthermore, a multilayer board can be formed by using a printed wiring board as an inner circuit board, laying a prepreg on the surface thereof, and further laying a metal foil such as a copper foil on the outside thereof, and heating and pressing the metal foil. The multilayer printed wiring board can be finished by forming a circuit by printing the metal foil on the surface of the multilayer board.

FIG. 1A shows a multilayer printed wiring board A manufactured using the glass cloth 4 prepared as described above. In this case, the warp 6 and the weft 7 of the glass cloth 4 are used.
Has a small curvature (waveform) in the thickness direction of the glass cloth yarn 3, and has a smooth waveform.
When a thermal shock acts on the multilayer printed wiring board A, thermal stress is generated along the interface between the glass cloth 4 and the layer of the thermosetting resin 5 in the direction indicated by the arrow x. The force is divided into a vector in the thickness direction (y arrow) and a vector in the plane direction (z arrow) of the wiring board A, but the curvature (waveform) of the glass cloth yarn 3 is small. The component force in the direction of the arrow (arrow) decreases, and the component force in the direction (z direction) of the layer of the thermosetting resin 5 having a low elastic modulus increases, so that the stress is relaxed. This can prevent the separation from occurring.

The same applies to the laminate B shown in FIG. That is, even in the laminated board B, the curvature (waveform) of the glass cloth yarn 3 constituting the warp yarn 6 and the weft yarn 7 of the glass cloth 4 in the thickness direction is small,
Waveform is smooth. Therefore, a thermal shock acts on the laminate B, and a thermal stress is generated in the direction of the arrow x along the interface between the glass cloth 4 and the layer of the thermosetting resin 5, and the stress of the laminate B of this stress is generated. Thickness direction (y arrow) and plane direction (z
Similarly, the component force indicated by the arrow is in the thickness direction (y
The component force in the direction of the arrow (arrow) decreases, and the component force in the direction (z direction) of the layer of the thermosetting resin 5 having a low elastic modulus increases, so that the stress is relaxed. This can prevent the separation from occurring.

FIG. 1 (b) shows the cross section of the glass cloth 4 of the multilayer printed wiring board A manufactured using the glass cloth 4 prepared as described above and the density distribution of the glass components. Cloth 4 prepared as above
Since the distance between the warp yarns 6 and the weft yarns 7 is large, the density of the glass components at the intersections of the warp yarns 6 and the weft yarns 7 and the sparse spacing of the glass components between them are increased. Since the flatness of the yarn 3 is large, the difference between the degree at which the glass component becomes dense at the intersection of the warp yarn 6 and the weft yarn 7 and the degree at which the glass component becomes sparse during this time become small. For this reason, when a thermal shock is applied to the multilayer printed wiring board A, the strain stress generated between the glass cloth 4 and the thermosetting resin 5 due to the difference in the thermal expansion coefficient between the resin and the glass is reduced. It is possible to prevent the occurrence of peeling between the glass cloth 4 and the layer of the thermosetting resin 5.

The same applies to the laminate B shown in FIG. That is, since the distance between the warp yarn 6 and the weft yarn 7 of the glass cloth 4 is large even in the laminated plate B, the density of the glass component at the intersection of the warp yarn 6 and the weft yarn 7 and the sparse interval of the glass component therebetween are large. In addition, since the flatness of the glass yarn 3 constituting the warp 6 and the weft 7 is large, the degree at which the glass component at the intersection of the warp 6 and the weft 7 becomes dense, and the degree at which the glass component therebetween becomes sparse. Is smaller. For this reason, when a thermal shock is applied to the multilayer printed wiring board A, the strain stress generated between the glass cloth 4 and the thermosetting resin 5 due to the difference in the thermal expansion coefficient between the resin and the glass is reduced. It is possible to prevent the occurrence of peeling between the glass cloth 4 and the layer of the thermosetting resin 5.

[0025]

The present invention will now be illustrated by examples. (Example 1) An epoxy resin varnish having the composition shown in Table 2 was prepared. Next, a glass cloth of E glass in Table 3a was impregnated with an epoxy resin varnish, and then heated and dried at a temperature of 150 ° C. for 5 minutes to remove the solvent, whereby the resin content was 50% by weight. A prepreg having a melt viscosity of 600 poise was obtained.

On the other hand, the thickness is 0.1 mm, and the thickness of the copper foil is 35 μm.
The copper foil on both sides of the glass epoxy double-sided copper-clad laminate was subjected to printed wiring processing to form a signal circuit, and the surface of the signal circuit was blackened to prepare an inner layer circuit board. Then, the prepreg was laminated one by one on both the front and back surfaces of the inner circuit board, and a copper foil having a thickness of 18 μm was laminated on the outside thereof, and this was heated and heated at 170 ° C. under a pressure of 50 kg / cm ² for 70 minutes. By forming a four-layer board by pressure molding, and further processing the printed wiring such as through-hole plating and resist to form an outer layer circuit,
A four-layer multilayer printed wiring board was manufactured.

(Example 2) A prepreg was prepared in the same manner as in Example 1 except that the E glass cloth shown in Table 3b was used, and a multilayer printed wiring board was manufactured. (Example 3) A prepreg was prepared in the same manner as in Example 1, except that the E glass cloth shown in Table 3c was used.
Further, a multilayer printed wiring board was manufactured.

Example 4 A prepreg was prepared in the same manner as in Example 1 except that the E glass cloth shown in Table 3d was used, and a multilayer printed wiring board was manufactured. (Example 5) A prepreg was prepared in the same manner as in Example 1 except that the E glass cloth of Table 3e was used.
Further, a multilayer printed wiring board was manufactured.

(Example 6) Using a prepreg 10a prepared using the E glass cloth shown in Table 3a and a prepreg 10c prepared using the E glass cloth shown in Table 3c,
The prepregs 10a and 10c are provided on the inner circuit board 1 in the configuration of FIG.
Then, a multilayer printed wiring board was manufactured in the same manner as in Example 1 except that the copper foil 8 was stacked.

(Example 7) Using a prepreg 10b prepared using the E glass cloth shown in Table 3b and a prepreg 10d prepared using the E glass cloth shown in Table 3d,
The prepregs 10b and 10d are added to the inner circuit board 1 in the configuration of FIG.
Then, a multilayer printed wiring board was manufactured in the same manner as in Example 1 except that the copper foil 8 was stacked.

Comparative Example 1 A prepreg was prepared in the same manner as in Example 1 except that the E glass cloth shown in Table 3f was used, and a multilayer printed wiring board was manufactured. (Comparative Example 2) A prepreg was prepared in the same manner as in Example 1 except that E glass cloth of g in Table 3 was used.
Further, a multilayer printed wiring board was manufactured.

Comparative Example 3 A prepreg was prepared in the same manner as in Example 1, except that the E glass cloth shown in Table 3h was used, and a multilayer printed wiring board was manufactured. (Comparative Example 4) Using the prepreg 10f prepared using the E glass cloth shown in Table 3f and the prepreg 10g prepared using the E glass cloth shown in Table 3g, the inner circuit board 1 having the configuration shown in FIG. Then, the prepregs 10f and 10g and the copper foil 8 were superimposed on each other, and thereafter, a multilayer printed wiring board was manufactured in the same manner as in Example 1.

(Comparative Example 5) Using 10 g of prepreg prepared using E glass cloth of Table 3g and 10 h of prepreg prepared using E glass cloth of Table 3h,
8, prepregs 10g and 10h
Then, a copper foil 8 was overlaid, and thereafter a multilayer printed wiring board was manufactured in the same manner as in Example 1.

[0034]

[Table 2]

[0035]

[Table 3]

With respect to the glass cloth used in Examples 1 to 7 and Comparative Examples 1 to 5, 1 cm ^{2 of} warp and weft was used.
The number of intersections per hit, the overlap area at the intersection of the warp and weft, the ratio of the minor axis a to the major axis b of the cross section of the glass cloth yarn (a / b), and the period of the waveform of the glass cloth yarn were measured. The results are shown in Tables 4 and 5. The four-layer multilayer printed wiring boards obtained in Examples 1 to 7 and Comparative Examples 1 to 5 were measured for heat resistance to moisture absorption. The test was conducted by leaving the sample at 40 ° C. and 90% RH for 96 hours to absorb moisture, and immersing the sample in a solder bath at 260 ° C. for 20 seconds, and by placing the sample at 60 ° C. and 90% RH for 96 hours. Leave it to absorb moisture and immerse it in a 260 ° C. solder bath for 20 seconds.
It was set to K. The results are shown in Tables 4 and 5. The number of tests is shown in the denominator, and the number of OK is shown in the numerator.

[0037]

[Table 4]

[0038]

[Table 5]

As can be seen from Tables 4 and 5, each of the examples manufactured using the glass cloth satisfying the conditions specified in the present invention has high heat resistance to moisture absorption and excellent heat shock resistance. It is confirmed. Example 8 An epoxy resin varnish having the composition shown in Table 2 was prepared. Next, an epoxy resin varnish was impregnated into the glass cloth of E glass in Table 3a, and then heated and dried at a temperature of 150 ° C. for 5 minutes to remove the solvent, thereby obtaining a resin content of 45% by weight. A prepreg having a melt viscosity of 650 poise was obtained.

Then, four prepregs were laminated, and a copper foil having a thickness of 18 μm was laminated on the outside of the prepregs. The prepregs were heated and pressed at 170 ° C. under a pressure of 50 kg / cm ² for 70 minutes. A glass-epoxy double-sided copper-clad laminate was manufactured. (Example 9) A prepreg was prepared in the same manner as in Example 8, except that the E glass cloth shown in Table 3b was used.
Further, a glass epoxy double-sided copper-clad laminate was manufactured.

Example 10 A prepreg was prepared in the same manner as in Example 8 except that the E glass cloth shown in Table 3c was used, and a glass epoxy double-sided copper-clad laminate was produced. (Example 11) A prepreg was prepared in the same manner as in Example 8 except that the E glass cloth shown in Table 3d was used, and a glass epoxy double-sided copper-clad laminate was produced.

Example 12 A prepreg was prepared in the same manner as in Example 8 except that the E glass cloth shown in Table 3e was used, and a glass epoxy double-sided copper-clad laminate was produced. (Example 13) Using the prepreg 10a prepared by using the E glass cloth of Table 3a and the prepreg 10c prepared by using the E glass cloth of Table 3c, the prepregs 10a and 10c having the configuration of FIG. A copper-clad double-sided glass-epoxy laminate was produced in the same manner as in Example 8, except that the copper foil 8 was laminated.

Example 14 Using a prepreg 10b prepared using the E glass cloth shown in Table 3b and a prepreg 10d prepared using the E glass cloth shown in Table 3d, a prepreg having the configuration shown in FIG. A glass epoxy double-sided copper-clad laminate was manufactured in the same manner as in Example 8 except that 10b, 10d and the copper foil 8 were stacked.

(Comparative Example 6) A prepreg was prepared in the same manner as in Example 8 except that the E glass cloth shown in Table 3f was used, and a glass epoxy double-sided copper-clad laminate was produced. (Comparative Example 7) A prepreg was prepared in the same manner as in Example 8, except that the E glass cloth of g in Table 3 was used.
Further, a glass epoxy double-sided copper-clad laminate was manufactured.

Comparative Example 8 A prepreg was prepared in the same manner as in Example 8, except that the E glass cloth shown in Table 3h was used, and a glass epoxy double-sided copper-clad laminate was produced. (Comparative Example 9) Using the prepreg 10f prepared using the E glass cloth f shown in Table 3 and the prepreg 10g prepared using the E glass cloth g shown in Table 3, the prepregs 10f and 10g were configured as shown in FIG. A copper-clad double-sided glass-epoxy laminate was produced in the same manner as in Example 8, except that the copper foil 8 was laminated.

(Comparative Example 10) Using the prepreg 10g prepared by using the E glass cloth of Table 3g and the prepreg 10h prepared by using the E glass cloth of Table 3h, the prepreg having the configuration shown in FIG. A glass epoxy double-sided copper-clad laminate was manufactured in the same manner as in Example 8 except that 10 g, 10 h and the copper foil 8 were stacked.

Examples 8 to 14 and Comparative Examples 6 to 1
With respect to the laminate obtained in Example No. 0, a moisture absorption heat resistance test and a PCT test were performed. The moisture absorption heat resistance test was conducted at 60 ° C. for 9 hours.
It was left for 144 hours under the condition of 0% RH to absorb moisture, and this was immersed in a solder bath at 260 ° C. for 30 seconds.
In the CT test, a sample treated at 121 ° C. for 120 minutes was subjected to 26
The sample was immersed in a solder bath at 0 ° C. for 30 seconds, and the sample which did not peel was evaluated as OK. The results are shown in Tables 6 and 7.
The number of tests is shown in the denominator, and the number of OK is shown in the numerator.

[0048]

[Table 6]

[0049]

[Table 7]

As can be seen from Tables 6 and 7, it is confirmed that each of the examples manufactured using the glass cloth satisfying the conditions specified in the present invention has excellent thermal shock resistance.

[0051]

As described above, the present invention relates to a prepreg made by impregnating and drying a glass cloth with a thermosetting resin, assuming that the thickness of the glass cloth is X μm, the warp and the weft of the glass cloth. Since the number of intersections per 1 cm ² is (130-X / 2) to (230-X / 2) / cm ² , the interval between the warp yarns and the weft yarns becomes longer and the warp yarns and the weft yarns become longer. The curvature of the bending (waveform) of the glass cloth yarn constituting the glass cloth yarn becomes smaller, the waveform of the glass cloth yarn becomes smoother, and the component force in the thickness direction of the glass cloth when the thermal shock is applied becomes smaller. It can prevent the occurrence of peeling between the glass cloth and the thermosetting resin layer.Moreover, the denseness of the glass component at the intersection of the warp and the weft and the sparse spacing of the glass component between them are Big Therefore, the strain stress generated between the glass cloth and the thermosetting resin layer due to the difference in the coefficient of thermal expansion between the resin and the glass when a thermal shock is applied can be reduced. It is possible to prevent separation from occurring between the resin layer and the resin layer.

Further, in the present invention, assuming that the thickness of the glass cloth is X μm, the overlapping area at one intersection between the warp and the weft is X / 300 mm ² or more. By increasing the area of the intersection, the difference between the density and the sparseness of the glass component can be reduced, and when a thermal shock is applied, the difference between the coefficient of thermal expansion of the resin and the glass causes the difference between the glass cloth and the thermosetting resin layer. It is possible to reduce the strain stress generated between the glass cloth and the separation between the glass cloth and the thermosetting resin layer.

Further, according to the present invention, as the glass cloth, a glass cloth yarn constituting a warp or a weft has a substantially elliptical cross-sectional shape which is flat in the thickness direction of the glass cloth, and the elliptical minor axis a and major axis b The ratio (a / b) of the glass cloth yarn is 0.1 or less, so that the degree of flatness of the glass cloth yarn is large, and the degree of the glass component at the intersection of the warp and the weft becomes dense, It can reduce the difference between the degree of sparse component and the difference between the glass and the thermosetting resin due to the difference in the coefficient of thermal expansion between the resin and the glass when a thermal shock is applied. This makes it possible to reduce the resulting strain stress and prevent the occurrence of peeling between the glass cloth and the thermosetting resin layer.

In addition, according to the present invention, when the glass cloth has a thickness of 170 μm or less, the glass cloth having a waveform cycle of 1.2 mm or more, which appears in a cross section in the thickness direction of the glass cloth, 17 thickness
In the case of a glass cloth exceeding 0 μm, a glass cloth yarn having a waveform cycle of 1.8 mm or more appearing in a cross section in the thickness direction of the glass cloth is used. The curvature of the glass cloth becomes smaller, the waveform of the glass cloth yarn becomes smoother, and the component of the stress in the thickness direction of the glass cloth when a thermal shock is applied becomes smaller. This can prevent the occurrence of peeling between them.

[Brief description of the drawings]

FIGS. 1A and 1B show an example of a multilayer printed wiring board according to the present invention, in which FIG. 1A is a partial cross-sectional view, and FIG.

FIG. 2 shows an example of a laminate according to the present invention,
(A) is a partial cross-sectional view, (b) is a cross-sectional view and glass
It is a figure which shows a close relationship.

3A and 3B show an example of a conventional multilayer printed wiring board, in which FIG. 3A is a partial cross-sectional view, and FIG. 3B is a view showing a cross-sectional view and a sparse-dense relationship of glass.

FIG. 4 shows an example of a conventional laminated plate, and (a)
FIG. 2 is a partial cross-sectional view, and FIG.

FIG. 5 is a schematic diagram showing a layer configuration of Example 6.

FIG. 6 is a schematic diagram showing a layer configuration of a seventh embodiment.

FIG. 7 is a schematic diagram showing a layer configuration of Comparative Example 4.

FIG. 8 is a schematic diagram showing a layer configuration of Comparative Example 5.

FIG. 9 is a schematic view showing a layer configuration of Example 13.

FIG. 10 is a schematic view showing a layer configuration of Example 14;

FIG. 11 is a schematic diagram showing a layer configuration of Comparative Example 9.

FIG. 12 is a schematic view showing a layer configuration of Comparative Example 10.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner layer circuit board 2 Inner layer circuit 3 Glass cloth yarn 4 Glass cloth 5 Thermosetting resin 6 Warp 7 Weft

Continuation of the front page (72) Inventor Takashi Soraku 1048, Kazuma, Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. (56) References JP-A-5-78945 (JP, A) (58) Fields investigated (Int.Cl) . ^6, DB name) C08J 5/24 B32B 17/04 H05K 1/03

Claims (4)

(57) [Claims] 1. In a prepreg prepared by impregnating and drying a thermosetting resin in a glass cloth, assuming that the thickness of the glass cloth is X μm, the number of intersections per 1 cm ² between the warp and the weft of the glass cloth is as follows. , (130-X / 2) to (230-X / 2) pieces / cm ² , and the thickness is X μm, the warp and the weft are
Overlapping area in one intersection, X / 300 mm ² or more
The glass cloth that is above and composes warp and weft yarns
The yarn has a substantially elliptical shape that is flat in the thickness direction of the glass cloth.
It has a cross-sectional shape, and the ratio of the minor axis a to the major axis b of the ellipse
(A / b) is 0.1 or less and the thickness is 17
In the case of a glass cloth of 0 μm or less,
Waveform of glass cloth yarn appearing in cross section in thickness direction
A prepreg characterized by using a material having a period of 1.2 mm or more . 2. In a prepreg prepared by impregnating and drying a thermosetting resin in a glass cloth, if the thickness of the glass cloth is X μm, the warp of the glass cloth is used.
And the number of intersections per 1 cm ^{2 of the} weft is (130−X / 2) to (230−X / 2) / cm ² , and the thickness is X μm, the warp and the weft
Overlapping area in one intersection, X / 300 mm ² or more
The glass cloth that is above and composes warp and weft yarns
The yarn has a substantially elliptical shape that is flat in the thickness direction of the glass cloth.
It has a cross-sectional shape, and the ratio of the minor axis a to the major axis b of the ellipse
(A / b) is 0.1 or less and the thickness is 17
In the case of glass cloth exceeding 0 μm, use glass cloth
Of glass cloth yarn appearing on the cross section in the thickness direction
A prepreg characterized in that a shape having a period of 1.8 mm or more is used. 3. A laminate comprising the prepreg according to claim 1 or 2 . 4. A multilayer printed wiring board comprising the prepreg according to claim 1 or 2 .