JPH0946050A - Multilayered substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the amount of resin flowing out to an opening part by forming a prepreg facing the opening part with resin whose melting viscosity at the end part is higher than the resin melting viscosity at the other part. SOLUTION: As the base material constituting a multilayered substrate 1, inorganic fiber such as glass is used. In a prepreg 3, impregnated with resin vanish in the base material, the resin melting viscosity of the prepreg is set at 100-2,000 poise for epoxy-resin impregnated material, impregnated with epoxy resin, and the resin melting viscosity of an end part 8 within 20mm from the edge facing the opening part is set at 1,000 poise or more and 50,000 poise or less in comparison with the other part of the prepreg 3. When the resin melting viscosity has the value lower than the lower limit, the flow of the resin is more. When the viscosity has the value higher than the upper limit, the fluidity of the resin becomes worse and the remaing void is generated. When hot air is blown to the end part 8 facing the opening part 4 of the prepreg 3 for heating, and the impregnating resin varnish is melted and hardened, the amount of the resin flowing out to the opening part can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer substrate having an opening used for electric equipment, electronic equipment, communication equipment and the like.

[0002]

2. Description of the Related Art Conventionally, a multilayer substrate having an opening is formed by impregnating a base material with resin varnish and stacking dried prepregs on top of each other, and further stacking a metal foil-bonded substrate on the outside thereof. Can be sandwiched between hot plates and heated and pressed to obtain.

FIG. 3 is a sectional view of the above-mentioned multilayer substrate. This multilayer substrate 1 is a multilayer substrate 1 used for a pin grid array or a ball grid array, and has an opening 4 for mounting a semiconductor chip formed in the center.

However, as shown in the figure, the multi-layer substrate 1 having the opening 4 is subjected to the heating and pressure molding, and the prepreg 3
The resin 7 impregnated in the resin melts, flows out, and flows into the opening 4. The resin 7 that has flowed out flows to the terminal electrode 5 formed in the opening 4 and adheres to the surface of the terminal electrode 5, and the terminal electrode 5 to which the resin 7 adheres cannot be plated. was there.

A rigid board 2a as shown in FIG.
The rigid flexible multilayer substrate 10 in which the flexible substrate 9 and the flexible substrate 9 are combined, the prepreg 3 is superposed on the flexible substrate 9 in the same manner as described above, and the rigid substrate 2a is superposed on the outer side of the rigid body between the hot plates. It is manufactured by sandwiching and heating and pressing.

However, during the heat and pressure molding, the rigid substrate 2 is placed in the opening 4 where the flexible substrate 9 is exposed.
The resin 7 of the prepreg 3 for adhering a to the flexible substrate 9 may flow into the flexible substrate 9. When the resin 7 flows into the flexible substrate 9 that constitutes the rigid-flexible multilayer substrate 10 as described above, the resin 7 that has flowed in
Thus, the flexible substrate 9 is prevented from being bent, and when the flexible substrate 9 is bent to a desired angle, a fold may occur near the joint portion 11 between the flexible substrate 9 and the rigid substrate 2a shown in FIG.

Further, in order to solve the above-mentioned problem of resin flow, heat and pressure molding was carried out using a low flow prepreg which was impregnated with a resin varnish in which the resin 7 was less likely to flow out and was dried. Although the resin melt can be prevented from flowing due to its high melt viscosity, the resin flowability is poor, so that when a plurality of sheets are used, a void is generated between the prepregs.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a multi-layer substrate having an opening, in which the amount of resin flowing out to the opening is small and the moldability is improved. To provide a good multilayer substrate.

[0009]

A multi-layer substrate according to claim 1 of the present invention is a multi-layer substrate having an opening, wherein the resin melt viscosity of an end 8 of the prepreg 3 facing the opening 4 is different from that of another portion. It is characterized by being formed from a resin having a higher melt viscosity than the resin melt viscosity of.

In the multilayer substrate according to claim 2 of the present invention, the prepreg 3 used in the laminated plate according to claim 1 is an epoxy resin impregnated material, and the resin melt viscosity of the end 8 of the prepreg 3 and other It is characterized in that the difference in resin melt viscosity between portions is 1,000 poises or more and 50,000 poises or less.

In the multilayer substrate according to claim 3 of the present invention, the prepreg 3 used in the laminated plate according to claim 1 is a polyimide resin impregnated material, and the resin melt viscosity of the end 8 of the prepreg 3 and other Difference in resin melt viscosity between parts is 10,000
It is characterized in that it is not less than poise and not more than 500,000 poise.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A multi-layer substrate according to the present invention is a multi-layer substrate having an opening, a base material is impregnated with a resin varnish, and a dried prepreg 3 is superposed thereon, and further, substrates 2 and 6 are superposed on the outside thereof. An opening 4 formed by integrating the combined pressure-subjects
Or the multilayer substrate 1 having the opening 4 formed by superposing the prepreg 3 on the substrate 2 and further superimposing and integrating the pressed body on which the metal foil is superposed.
The resin melt viscosity of the end portion 8 of the prepreg 3 facing the resin melt viscosity is higher than that of the other portion of the prepreg 3 in the multilayer substrate 1.

As the base material constituting the multi-layer substrate 1, inorganic fibers such as glass, organic fibers such as aramid, woven fabrics and non-woven fabrics, which are used alone or in combination, are used. Is a resin varnish containing a thermosetting resin such as an epoxy resin, a phenol resin, a melamine resin, or a polyimide resin alone, a modified product, or a mixture as a main component, and optionally a coupling agent, a flame retardant, or the like. can do.

In the prepreg 3 in which the base material is impregnated with a resin varnish, the resin melt viscosity is 100 to 2000 poise for the epoxy resin impregnated material impregnated with the epoxy resin, and the end within 20 mm from the end face facing the opening 4. The resin melt viscosity of the part 8 is preferably 1,000 poises or more and 50,000 poises or less, as compared with the resin melt viscosities of the other parts of the prepreg 3. Further, the polyimide resin impregnated material impregnated with the polyimide resin is 1000 to 3000 poise, and the end portion 8 within 20 mm from the end surface facing the opening 4 is used.
The resin melt viscosity of the above is 50000 or more when compared with the resin melt viscosity of the other parts of the prepreg 3,
It is preferably not more than poise. When the resin melt viscosity is lower than the lower limit, the resin flow is large, and when it is higher than the upper limit, the fluidity of the resin is deteriorated and residual voids are generated.

As a method of increasing the resin melt viscosity of the end portion 8 of the prepreg 3 facing the opening 4 higher than the resin melt viscosity of other portions, hot air is blown to the end portion 8 of the prepreg 3 or far infrared rays are emitted. The resin varnish impregnated in the prepreg 3 can be melted by applying, heating with a heat press, or the like, and further cured to increase the resin melt viscosity.

As the substrate 2 attached by the prepreg 3, a metal foil such as 1
A laminated board to which a copper foil having a thickness of 2 μm to 70 μm is attached, or a printed circuit board having a circuit formed on the metal foil of the laminated board is used.

The prepreg 3, the laminated board and the printed board are generally rectangular in shape, but when the multilayer board 1 having these as constituent elements is used for a semiconductor package,
Those each having an opening 4 formed in the center are used.

The opening 4 is formed in a concave shape in the center of the multilayer substrate 1 for mounting a semiconductor chip or the rigid substrate 2a such as the rigid flexible multilayer substrate 10.
On the other hand, one in which the flexible substrate 9 is formed in a stepped shape can be mentioned.

FIG. 1 is a sectional view of a pin grid array substrate which is an example of a semiconductor package using the multilayer substrate according to the present invention, and FIG. 2 is a sectional view of a rigid-flexible multilayer substrate showing an embodiment of the present invention. .

Hereinafter, the present invention will be described in detail. (Example) As shown in FIG. 1, the multilayer substrate 1 of the present invention is
A prepreg 3 having an opening 4 in which a base material is impregnated with a resin varnish, a printed board having a metal foil attached to the outside and a circuit pattern formed on the metal foil, and an opening 4 at the center of the circuit pattern and the board. And a printed circuit board on which is formed.

The printed circuit board constituting the multilayer board 1 has a thickness of 0.8 mm in which 35 μm copper foil is adhered on the front and back surfaces.
Epoxy resin impregnated material (R1766: manufactured by Matsushita Electric Works, Ltd.) is used, and a circuit pattern is formed on the copper foil by etching. In particular, the surface is exposed in the opening 4, and the printed circuit board on which the semiconductor chip is mounted has the terminal electrode 5 connected to the mounted semiconductor chip.

The prepreg 3 is a glass cloth substrate (7628AS manufactured by Asahi Schebel Co., Ltd.) and 100 parts by weight of an epoxy resin (YDB500 manufactured by Toto Kasei Co., Ltd.)
Section), dicyandiamide (Japan Carbite Co., Ltd.)
3 parts, 2E4MZ (manufactured by Shikoku Kasei Co., Ltd.) 0.2 parts,
Impregnated with 130 parts of DMF solvent with molten varnish,
Drying at 70 ℃, thickness 0.1mm, resin melt viscosity 1,
A 000 poise semi-cured product was formed.

Further, an opening 4 is bored in the prepreg 3, and a far-infrared ray is radiated to an end 8 of 10 mm width facing the opening 4, and the resin melt viscosity of the end 8 is 20,000.
Prepreg 3 of 0 poise and 50,000 poise was formed.

Each of the prepregs 3 is used, and each prepreg 3 is sandwiched between the substrates to form a body to be pressed,
The pressure member is arranged between a pair of metal plates, and the plurality of pressure members sandwiched between the pair of metal plates is arranged between a pair of heating plates to form a cushion material. Eight pieces of (kraft paper) are placed between the upper and lower heating plates and the metal plate closest to this heating plate, heated from room temperature to 120 ° C in 20 minutes, heated at 120 ° C for 20 minutes, and further to 180 ° C. 20
The temperature is raised in minutes, heating is performed at 180 ° C. for 90 minutes, pressurizing with a pressing force of 5 kg / cm ² for 5 minutes from the start of heating, and then 4
After molding at 0 kg / cm ² , the multilayer substrate 1 was molded by cooling under the same pressure.

The distance from the tip of the resin 7 flowing out from the end face of the obtained multilayer substrate 1 facing the opening 4 to the end face was measured and evaluated. Further, the obtained multilayer substrate 1 was etched to remove the copper foil on the surface, and the generation of voids was confirmed visually and by a magnifying glass. No place where residual voids were generated could be confirmed. The result shows that the resin melt viscosity of the end 8 of the prepreg 3 facing the opening 4 is 20,000.
The poise of Example 1 has a resin melt viscosity of 50,000.
A poise is shown in Table 1 as Example 2.

Here, in contrast to the above example, a prepreg 3 having a resin melt viscosity of 20,000 poise and having an opening 4 at the center was formed, and using this prepreg 3, a multilayer substrate was obtained in the same manner as above. 1 was molded. Further, a prepreg 3 having a resin melt viscosity of 500 poise and an opening 4 formed in the center was formed, and the prepreg 3 was used to mold the multilayer substrate 1 in the same manner as described above.

In the same manner as in the example, the multilayer substrate 1 obtained above was measured for the distance from the tip of the resin 7 flowing out from the end face facing the opening 4 to the end face, and was further etched to obtain the surface The copper foil was removed, and the occurrence of voids was confirmed visually and by a magnifying glass. The respective results obtained are shown in Table 1 as Comparative Examples 1 and 2.

[0028]

[Table 1]

Next, 1.4-bis (2-p-anilinopropylidene) benzene-bis-imide and 1-bis were added to a glass cloth substrate (7628AS, manufactured by Asahi Schwebel Co., Ltd.).
100 parts of a polyimide resin synthesized from 4-bis (2-m-anilinopropylidene) benzene, 70 parts of triallyl isocyanurate (manufactured by Nippon Kasei), BPA-AE
(Mitsui Toatsu Co., Ltd.) 70 parts, 2E4MZ (Shikoku Kasei Co., Ltd.)
0.1 part) was impregnated with 130 parts of DMF solvent melted varnish and dried at 140 ° C. to obtain a semi-cured prepreg 3 having a thickness of 0.1 mm and a resin melt viscosity of 2,000 poises.
Was formed. Further, a rectangular opening 4 is bored in this prepreg 3, and far infrared rays are irradiated to the end 8 having a width of 10 mm from the opening 4 to obtain a prepreg 3 having a resin melt viscosity of 50,000 poises and 500,000 poises. Formed.

The printed circuit board constituting the multi-layer circuit board 1 has a thickness of 0.8 m with copper foil of 35 μm attached on the front and back.
m polyimide resin impregnated material (R4705: manufactured by Matsushita Electric Works)
The copper foil used had a circuit pattern formed by etching.

The substrate and the prepreg 3 are used, and the prepreg 3 is sandwiched between the substrates to form a body to be pressed, and the body to be pressed is arranged between a pair of metal plates,
Furthermore, a plurality of pressure bodies sandwiched between the pair of metal plates are arranged between a pair of heating plates, and eight cushion materials (kraft paper) are placed between the upper and lower heating plates and this heating plate. It is placed between close metal plates and heated from room temperature to 130 ° C in 20 minutes, heated at 130 ° C for 20 minutes, further heated to 200 ° C in 20 minutes, heated at 200 ° C for 100 minutes, and heated. For 5 minutes from the start, a pressing force of 5 kg / cm ² was applied, after which molding was performed at 30 kg / cm ² and then cooling under the same pressure was performed to mold the multilayer substrate 1.

In the same manner as in the above example, the distance from the tip of the resin 7 flowing out from the end face facing the opening 4 of the obtained multilayer substrate 1 to the end face was measured and evaluated. further,
The obtained multilayer substrate 1 was etched to remove the copper foil on the surface, and the generation of voids was confirmed visually and by a magnifying glass.
No place where residual voids were generated could be confirmed. The results are shown in Table 2 with the resin melt viscosity of the end 8 of the prepreg 3 facing the opening 4 being 50,000 poise as Example 3 and the resin melt viscosity of 500,000 poise as Example 4. Show.

Here, in contrast to the above example, a prepreg 3 having a resin melt viscosity of 50,000 poise and having an opening 4 in the center was formed, and a multilayer substrate 1 was molded in the same manner as described above. Further, a prepreg 3 having a resin melt viscosity of 2,000 poise and an opening 4 formed in the center is formed,
The multilayer substrate 1 was molded in the same manner as above.

The distance from the tip to the end face of the resin 7 flowing out from the end face facing the opening 4 of the obtained multi-layer substrate 1 was measured and evaluated, and the multi-layer substrate 1 obtained above was evaluated. In the same manner as in Example 1, the multilayer substrate 1 was etched to remove the copper foil on the surface, and the occurrence of voids was confirmed visually and by a magnifying glass. The results are shown in Table 2 as Comparative Examples 3 and 4.

The results of Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Tables 1 and 2. Formability is the number of generated voids, and resin 7 is the length from the end face. evaluated.

[0036]

[Table 2]

[0037]

According to the present invention, the resin melt viscosity of the end portion 8 of the prepreg facing the opening of the multilayer substrate is formed to be higher than the resin melt viscosity of the other portions of the prepreg. The resin that flows out into the opening can be suppressed, and a multilayer substrate having no void and good moldability can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a multilayer substrate according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a multilayer substrate according to another embodiment of the present invention.

FIG. 3 is a sectional view of a conventional multilayer substrate.

FIG. 4 is a cross-sectional view of a conventional multilayer substrate.

FIG. 5 is a cross-sectional view in which a rigid flexible multilayer substrate is bent.

[Explanation of symbols]

 1 Multilayer Substrate 2 Substrate 3 Prepreg 4 Opening 5 Terminal Electrode 6 Substrate 7 Resin 8 End 9 Flexible Substrate 10 Rigid Flexible Multilayer Substrate

Claims (3)

[Claims] 1. A multilayer substrate having an opening, wherein the resin melt viscosity of the end (8) of the prepreg (3) facing the opening (4) is higher than that of the other portion. A multi-layer substrate characterized by being formed. 2. The prepreg (3) used in the laminated board according to claim 1 is an epoxy resin impregnated material, and the resin melt viscosity of the end (8) of the prepreg (3) and the resin melt of other portions. Viscosity difference of 1,000 poise or more, 50,000
A multi-layer substrate characterized by having a poise or less. 3. The prepreg (3) used in the laminate according to claim 1 is a polyimide resin impregnated material, and the resin melt viscosity of the end (8) of the prepreg (3) and the resin melt of other portions. Viscosity difference of 10,000 poise or more, 500,
A multi-layer substrate having a poise of 000 poise or less.