JPH1027968A - Multilayer wiring board - Google Patents

Abstract

(57) Abstract: A depression is formed on the upper and lower surfaces of an organic resin filler filled in a through hole of an insulating substrate, and a step is formed in the organic resin insulating layer due to the depression of the organic resin filler. As a result, disconnection occurs in the thin film wiring conductor. An insulating substrate (1) having a through hole (5) penetrating both upper and lower main surfaces, a conductive layer (6) extending from the upper surface of the insulating substrate (1) to the lower surface via an inner wall of the through hole (5), and an inside of the through hole (6). The filled organic resin filler 7 and the organic resin insulating layer 2 and the thin film wiring conductor 3 which are adhered on at least one main surface of the insulating substrate 1 are alternately arranged, and a part of the thin film wiring conductor 3 is provided. Is a multilayer wiring board comprising a multilayer wiring portion 4 electrically connected to the conductive layer 6, wherein the organic resin filler 7 is formed of a photocurable resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer wiring board, and more particularly to a multilayer wiring board used for a hybrid integrated circuit device, a semiconductor element housing package for housing a semiconductor element, and the like.

[0002]

2. Description of the Related Art Conventionally, a multilayer wiring board used for a hybrid integrated circuit device, a package for accommodating a semiconductor element, or the like, has its wiring conductor formed by a thick film forming technique such as the Mo-Mn method.

[0003] This Mo-Mn method is generally used for tungsten,
Organic solvents for high melting point metal powders such as molybdenum and manganese,
A solvent is added and mixed, and a paste-like metal paste is applied by printing on the outer surface of the green ceramic body in a predetermined pattern by a screen printing method. Then, a plurality of these layers are laminated and fired in a reducing atmosphere to obtain a high melting point. This is a method of sintering and integrating a metal powder and a green ceramic body.

Incidentally, the ceramic body on which the wiring conductor is formed is usually an oxide ceramic such as an aluminum oxide sintered body or a mullite sintered body, or an aluminum nitride having an oxide film adhered on the surface. Non-oxide ceramics such as a porous sintered body and a silicon carbide sintered body are used.

However, when the wiring conductor is formed by using the Mo-Mn method, the wiring conductor is formed by screen-printing a metal paste. Had the drawback that it could not be done.

In order to solve the above-mentioned drawbacks, a multi-layer wiring board formed using a thin film forming technique capable of miniaturization instead of forming the wiring conductor by the conventional thick film forming technique is used. It has become.

Such a multilayer wiring board is made of glass formed by impregnating a glass cloth woven with ceramics or glass fibers made of an aluminum oxide sintered body or the like having through holes penetrating both upper and lower main surfaces with an epoxy resin. An insulating substrate made of an epoxy resin or the like; a conductive layer made of copper led out from the upper surface of the insulating substrate to the lower surface via the inner wall of the through hole; and a thermosetting organic resin material such as an epoxy resin filled in the through hole And an organic resin insulating layer made of a thermosetting organic resin material such as an epoxy resin and a thin film wiring conductor made of copper are alternately disposed on at least one main surface of the insulating substrate. And a part of the thin film wiring conductor is electrically connected to the conductive layer, and the thin film wiring conductor of the multilayer wiring part is externally connected via the conductive layer. Or electrically connected to the gas circuit, so as to electrically connect the thin film wiring conductor between the multilayered wiring portion to be deposited and formed on the upper and lower main surfaces of the insulating substrate.

The multilayer wiring board is formed by applying copper to the upper surface, the inner wall and the lower surface of the through-hole by an electroless plating method and processing the same into a predetermined pattern by photolithography to form the insulating substrate. A conductive layer extending from the upper surface of the through hole to the lower surface via the inner wall of the through hole is applied, and then the inside of the through hole is filled with a thermosetting organic resin precursor of an epoxy resin and is thermally cured to fill the organic resin. After that, an insulating layer made of an organic resin such as an epoxy resin and a metal such as copper or aluminum are formed on the upper and / or lower surfaces of the insulating substrate by electroless plating. It is manufactured by alternately arranging a plurality of thin film wiring conductors formed by adopting a thin film forming technique such as a deposition method or a vapor deposition method and a photolithography technique.

[0009]

However, in this multilayer wiring board, a thermosetting organic resin precursor of an epoxy resin is filled in the through hole of the insulating substrate, and the precursor is heat-treated to be cured by heat. When forming a resin filler, it takes a long time for thermosetting of the thermosetting organic resin precursor,
The mass productivity of the multilayer wiring board becomes remarkably low and the volume of the thermosetting organic resin precursor decreases, and the upper and lower surfaces of the organic resin filler become recessed from the upper and lower surfaces of the insulating substrate,
As a result, when an organic resin insulating layer and a thin film wiring conductor are alternately arranged on the upper and lower surfaces of an insulating substrate to form a multilayer wiring portion,
A step is formed in the organic resin insulating layer due to a depression formed on the upper and lower surfaces of the organic resin filler, and this step has a disadvantage that the thin film wiring conductor is disconnected or the like.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and has as its object to provide a multi-layer wiring portion comprising an organic resin insulating layer and a thin-film wiring conductor on both upper and lower main surfaces of an insulating substrate. It is an object of the present invention to provide a multilayer wiring board which can be formed on a thin film wiring conductor without causing disconnection or the like.

According to the present invention, there is provided an insulating substrate having a through-hole penetrating both upper and lower main surfaces, a conductive layer extending from the upper surface of the insulating substrate to the lower surface through the inner wall of the through-hole, and filled in the through-hole. An organic resin filler, which is attached on at least one main surface of the insulating substrate, and an organic resin insulating layer and a thin film wiring conductor are alternately arranged and a part of the thin film wiring conductor is electrically connected to the conductive layer. A multilayer wiring board comprising a connected multilayer wiring portion, wherein the organic resin filler is formed of a photocurable resin.

Further, the present invention provides an organic resin filler comprising the above-mentioned photocurable resin having a particle size of 0.01 μm to 10 μm.
m is contained.

Further, the present invention is characterized in that the content of the filler is 10 to 80 parts by weight based on 100 parts by weight of the organic resin filler.

According to the multilayer wiring board of the present invention, since the organic resin filler filled in the through-holes penetrating the upper and lower main surfaces provided on the insulating substrate is formed of the photo-curable resin, the organic resin filler is used. It can be formed in a short time, and the mass productivity of the multilayer wiring board is significantly improved.

Further, according to the multilayer wiring board of the present invention, the photocurable resin is cured by light irradiation, and there is almost no volume reduction during curing. As a result, even if the organic resin insulating layers and the thin film wiring conductors are alternately arranged on the upper and lower surfaces of the insulating substrate to form a multilayer wiring portion, the organic resin insulating layers are all flattened. There is no occurrence of disconnection or the like in the thin film wiring conductor formed on the organic resin insulating layer.

Further, according to the multilayer wiring board of the present invention, since the wiring is formed on the insulating substrate by the thin film forming technique, the wiring can be miniaturized, and the wiring can be formed at an extremely high density.

[0017]

Next, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of a multilayer wiring board according to the present invention, wherein 1 is an insulating substrate, 2 is an organic resin insulating layer, and 3 is a thin film wiring conductor.

On the upper surface of the insulating substrate 1, a multilayer wiring portion 4 comprising an organic resin insulating layer 2 and a thin-film wiring conductor 3 is provided, and functions as a support member for supporting the multilayer wiring portion 4.

The insulating substrate 1 is made of an oxide ceramic such as an aluminum oxide sintered body or a mullite sintered body, or an aluminum nitride sintered body having an oxide film on its surface.
It is made of an electrically insulating material such as a non-oxide ceramic such as a silicon carbide sintered body, and a glass epoxy resin in which a cloth woven with glass fibers is impregnated with an epoxy resin. In the case of a compact, a suitable organic solvent and a solvent are added to raw material powders such as alumina, silica, calcia, and magnesia to form a slurry by mixing and adding the same to a conventionally known doctor blade method or calender roll. By forming the ceramic green sheet (ceramic raw sheet) by adopting the method,
Thereafter, the ceramic green sheet is subjected to an appropriate punching process so as to have a predetermined shape and a high temperature (about 16 ° C.).
(00 ° C.) or by mixing a raw material powder such as alumina with an appropriate organic solvent and a solvent to adjust the raw material powder and form the raw material powder into a predetermined shape by a press molding machine. About 1600 ° C
If it is made by firing at a temperature of, and made of glass epoxy resin, for example, impregnating the epoxy resin precursor into a cloth woven of glass fibers and heat curing the epoxy resin precursor at a predetermined temperature Produced by

The insulating substrate 1 is formed with a through hole 5 having a hole diameter of, for example, 0.3 mm to 0.5 mm penetrating through the upper and lower main surfaces. Conductive layers 6 are attached to the upper and lower surfaces of the insulating substrate 1.

The through-hole 5 electrically connects the thin-film wiring conductor 3 of the multilayer wiring portion 4 formed on the upper surface of the insulating substrate 1 to be described later and an external electric circuit, or is formed on the upper and lower main surfaces of the insulating substrate 1. When the multilayer wiring portion 4 is provided, it acts as a forming hole for forming a conductive layer 6 for electrically connecting the thin film wiring conductors 3 of the multilayer wiring portion 4 on both main surfaces, and a drill is formed in the insulating substrate 1. A predetermined position and a predetermined shape of the insulating substrate 1 are formed by performing a hole forming method.

Further, a conductive layer 6 is formed on the inner wall of the through hole 5 and on the upper and lower surfaces of the insulating substrate 1, and the conductive layer 6 is made of a metal containing nickel as a main component. 40 g of nickel sulfate /
Liter, sodium citrate 24 grams / liter,
1 μm thick using an electroless plating bath consisting of 14 g / l of sodium acetate, 20 g / l of sodium hypophosphite, and 5 g / l of ammonium chloride.
Then, a nickel layer having a thickness of 40 μm to 40 μm is applied, and then the nickel layer is processed into a predetermined pattern by an etching method so that both ends of the through-hole 5 are led out to the upper and lower surfaces of the insulating substrate 1. Is formed.

The conductive layer 6 electrically connects the thin-film wiring conductors 3 of the multilayer wiring portion 4 provided on the main surface of the insulating substrate 1 to an external electric circuit, or is provided on both upper and lower main surfaces of the insulating substrate 1. It functions to electrically connect the thin film wiring conductors 3 of the respective multilayer wiring portions 4 to be provided.

The conductive layer 6 has at least a region attached to the inner wall of the through hole 5 made of a metal containing nickel as a main component and having good bonding properties with an organic resin. When the organic resin filler 7 described later is filled, the bonding strength between the conductive layer 6 and the organic resin filler 7 is increased, and peeling between the conductive layer 6 and the organic resin filler 7 even when an external force is applied. Does not occur, and the organic resin filler 7 can be securely fixed at a predetermined position of the through hole 5.

Further, the through hole 5 formed in the insulating substrate 1 is further filled with an organic resin filler 7, and the through hole 5 is completely filled with the organic resin filler 7.
At the same time, both end surfaces of the organic resin filler 7 are flush with the surface of the conductive layer 6 adhered to the upper and lower main surfaces of the insulating substrate 1.

The organic resin filler 7 comprises an epoxy resin,
Polyimide resin, bismaleimide triazide resin, polyphenylene ether resin, composed of photosensitive organic resin such as fluororesin, for example, when composed of photosensitive epoxy resin, phenol novolak resin, methylol melamine, diallyl diazonium salt propylene Glycol monomethyl ether acetate is added and mixed to obtain a paste-like photosensitive epoxy resin precursor, and the paste is filled into a through-hole 5 provided in the insulating substrate 1. Thereafter, the filled photosensitive epoxy resin precursor is added to the photosensitive epoxy resin precursor. 10 mW / cm ^{2 to} 30 mW / cm with an exposure machine using a high-pressure mercury lamp or the like
The energy of ² is irradiated for 1.5 to 4.5 minutes,
It is formed by photo-curing a photosensitive epoxy resin precursor by applying energy of ３3 J / cm ³ . In this case, the photo-curing of the photosensitive epoxy resin precursor is performed in an extremely short time as compared with the thermosetting resin, and the mass production of the multilayer wiring board is smaller than the case where the organic resin filler is formed with the thermosetting organic resin. The properties are significantly improved. Further, the photosensitive epoxy resin precursor hardly causes a volume reduction during the photo-curing, so that an organic resin insulating layer 2 and a thin film wiring conductor 3 described later are alternately arranged on the upper surface of the insulating substrate 1. When the multi-layer wiring portion 4 is formed in this manner, each of the organic resin insulating layers 2 becomes flat, and the thin film wiring conductor 3 formed on the organic resin insulating layer 2 does not break.

The organic resin filler 7 made of the photocurable organic resin has a particle size of 0.01 μm to 10 μm.
μm filler, when 10 parts by weight to 80 parts by weight of the organic resin filler 7 is 100 parts by weight,
The filling of the organic resin filler 7 into the through-holes 5 provided in the insulating substrate 1 is favorably performed, and the upper and lower surfaces of the organic resin filler 7 are subjected to roll buff polishing or the like so that the upper and lower surfaces of the organic resin filler 7 are electrically conductive layers. When it is on the same plane as 6, its workability is good.

As the filler to be contained in the organic resin filler 7, a solid having good light transmittance such as an inorganic fine powder such as SiO ₂ or a fine powder of a thermosetting resin is preferably used. When the thickness is less than 0.01 μm, the filling property of the organic resin filler 7 into the through holes 5 provided in the insulating substrate 1 is deteriorated, and concave portions are formed on both upper and lower surfaces where a large amount of voids are formed in the organic resin filler 7. If the thickness exceeds 10 μm, the curing at the time of photocuring becomes incomplete, and the adhesion of the organic resin filler 7 to the through holes 5 provided in the insulating substrate 1 is deteriorated, and the organic resin filler 7 There is a risk that workability such as roll buff polishing on the surface may deteriorate. Therefore, it is preferable that the particle size of the filler contained in the organic resin filler 7 is in the range of 0.01 μm to 10 μm.

If the content of the filler contained in the organic resin filler 7 is less than 10 parts by weight based on 100 parts by weight of the organic resin filler 7, shrinkage of the organic resin filler 7 at the time of photocuring. And large concave portions are formed on both upper and lower surfaces of the organic resin filler 7, the filling property of the organic resin filler 7 into the through-hole 5 is deteriorated, and the workability by roll buff polishing or the like tends to deteriorate. When the content exceeds 80 parts by weight, the curing of the organic resin filler 7 during photocuring becomes incomplete, and the adhesion of the organic resin filler 7 to the through holes 5 provided in the insulating substrate 1 deteriorates. There is a risk that it will. Therefore, the content of the filler contained in the organic resin filler 7 is 1 when the content of the organic resin filler 7 is 100 parts by weight.
It is preferable to set the range of 0 to 80 parts by weight.

Further, the insulating substrate 1 is provided with a multilayer wiring portion 4 on the upper surface of which an organic resin insulating layer 2 and thin film wiring conductors 3 are alternately arranged in multiple layers.
Are electrically connected to the conductive layer 6.

The organic resin insulating layer 2 constituting the multilayer wiring portion 4 serves to electrically insulate the thin film wiring conductors 3 located above and below, and the thin film wiring conductors 3 serve as transmission paths for transmitting electric signals. Works.

The organic resin insulating layer 2 of the multilayer wiring section 4 is made of an epoxy resin. For example, when the organic resin insulating layer 2 is made of an epoxy resin, bisphenol A type epoxy resin, novolak type epoxy resin, glycidyl ester type epoxy resin, etc. A curing agent such as an imidazole-based curing agent and an acid anhydride-based curing agent is added and mixed to obtain a paste-like epoxy resin precursor, and the epoxy resin precursor is applied to the upper portion of the insulating substrate 1 by spin coating. After a while
This is formed by heat-treating with heat of about 80 ° C. to 200 ° C. for 0.5 to 3 hours and heat curing.

The organic resin insulating layer 2 has a through hole 8 having a minimum diameter of about 1.5 times the thickness of the organic resin insulating layer 2 at a predetermined position. Acts as a forming hole for forming a through-hole conductor 9 for electrically connecting each of the thin film wiring conductors 3 positioned above and below via an organic resin insulating layer 2 described later.

The through holes 8 provided in the organic resin insulating layer 2 are formed at predetermined positions by, for example, a photolithography technique, specifically, applying a resist material onto the organic resin insulating layer 2 and exposing and developing the resist material. A window having a predetermined shape is formed, and then an etchant is disposed on the window of the resist material, the organic resin insulating layer 2 located on the window of the resist material is removed, and a hole ( A through hole is formed, and finally, the resist material is peeled off from the organic resin insulating layer 2 and removed.

Further, a thin-film wiring conductor 3 having a predetermined pattern is provided on the upper surface of each organic resin insulating layer 2, and a through-hole conductor 9 is provided on the inner wall of a through hole 8 provided in each organic resin insulating layer 2. Each of the thin-film wiring conductors 3 positioned above and below the organic resin insulating layer 2 with the through-hole conductor 9 interposed therebetween is electrically connected.

The thin-film wiring conductor 3 and the through-hole conductor 9 provided on the upper surface of each of the organic resin insulating layers 2 and in the through-holes 8 are made of a metal material such as copper, nickel, gold, or aluminum by electroless plating or vapor deposition. For example, in the case of being formed of copper, copper sulfate is formed on the upper surface of the organic resin insulating layer 2 and the inner surface of the through hole 8 when the thin film forming technique and the etching technique are employed. 0.06 mol / liter, formalin 0.3 mol /
Liter, sodium hydroxide 0.35 mol / l,
A copper layer having a thickness of 1 μm to 40 μm is applied using an electroless copper plating bath composed of 0.35 mol / liter of ethylenediaminetetraacetic acid, and thereafter, the copper layer is processed into a predetermined pattern by an etching method. Between each organic resin insulating layer 2 and through hole 8 in each organic resin insulating layer 2
It is arranged on the inner wall. In this case, since the thin-film wiring conductor 3 is formed by a thin-film forming technique, the wiring can be miniaturized, whereby the thin-film wiring conductor 3 can be formed at an extremely high density.

The multi-layer wiring portion 4 formed by alternately arranging the organic resin insulating layers 2 and the thin film wiring conductors 3 in multiple layers has a through hole 5 provided in the insulating substrate 1 and an organic resin filler 7. Since it is completely buried, even if the organic resin insulating layer 2 is formed on the main surface of the insulating substrate 1, the organic resin insulating layer 2 is kept flat and formed on each organic resin insulating layer 2. It is possible to effectively prevent the thin film wiring conductor 3 from being disconnected or the like.

When the thickness of each organic resin insulating layer 2 exceeds 100 μm, the multi-layer wiring portion 4 employs a photolithography technique in the organic resin insulating layer 2 to form a through hole 8, so that the etching processing time is reduced. When the length is longer, it is difficult to form the through hole 8 into a desired sharp shape. When the thickness is less than 5 μm, the roughness for increasing the bonding strength of the organic resin insulating layer 2 located above and below the upper surface of the organic resin insulating layer 2 is increased. When performing surface processing, there is a risk that unnecessary holes may be formed in the organic resin insulating layer 2 and unnecessary electrical short circuits may be caused in the thin film wiring conductors 3 located above and below. Therefore, it is preferable that the thickness of each of the organic resin insulating layers 2 is in the range of 5 μm to 100 μm.

Further, each thin film wiring conductor 3 of the multilayer wiring portion 4
When the thickness is less than 1 μm, the electric resistance of each thin-film wiring conductor 3 becomes large, and it becomes difficult to transmit a predetermined electric signal to each thin-film wiring conductor 3.
If the thickness exceeds 0 μm, when the thin film wiring conductor 3 is applied to the organic resin insulating layer 2, a large stress is present inside the thin film wiring conductor 3, and the thin film wiring conductor 3 is easily peeled off from the organic resin insulating layer 2 due to the intrinsic stress. It will be. Therefore, it is preferable that the thickness of each thin-film wiring conductor 3 of the multilayer wiring portion 4 be set in a range of 1 μm to 40 μm.

Further, the surface of the thin film wiring conductor 3 has a center line average roughness (Ra) of 0.05 μm ≦ Ra ≦ 5 μm.
m, height of unevenness at 2.5 mm length of surface (P
The count value of c) is determined to be not less than 30,000 at 0.01 μm ≦ Pc ≦ 0.1 μm and 300 at 0.1 μm ≦ Pc ≦ 1 μm.
0 to 10000, 1 μm ≦ Pc ≦ 10 μm is 50
If the roughness is reduced to 0 or less, the bonding area between the organic resin insulating layer 2 and the thin film wiring conductor 3 becomes extremely large, and as a result, the adhesion between the organic resin insulating layer 2 and the thin film wiring conductor 3 becomes large. Is significantly improved, and even when an external force is applied to the organic resin insulating layer 2 and the thin film wiring conductor 3, the external force does not cause separation between the organic resin insulating layer 2 and the thin film wiring conductor 3; Can be made extremely strong. Therefore, the surface of the thin film wiring conductor 3 has a center line average roughness (Ra) of 0.05 μm ≦ Ra ≦ 5 μm and a surface of 2.5 μm.
The count value of the height (Pc) of the unevenness in the length of mm is 0.010000 ≦ Pc ≦ 0.1 μm.
0.1 μm ≦ Pc ≦ 1 μm: 3000 to 10,000
It is preferable that the number of particles is roughened so that 1 μm ≦ Pc ≦ 10 μm becomes 500 or less.

Thus, according to the multilayer wiring board of the present invention,
When the conductive layer 6 attached to the lower surface of the insulating substrate 1 is connected to an external electric circuit, each thin film wiring conductor 3 of the multilayer wiring portion 4 formed on the upper surface of the insulating substrate 1 is electrically connected to the external electric circuit. It will be connected.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. Is provided only on the upper surface of the substrate, the multilayer wiring portion 4 including the organic resin insulating layer 2 and the thin film wiring conductor 3 is provided. However, the multilayer wiring portion 4 may be provided only on the lower surface side of the insulating substrate 1 or provided on both upper and lower main surfaces. You may.

[0043]

According to the multilayer wiring board of the present invention, since the organic resin filler filled in the through-hole formed in the insulating substrate and penetrating both upper and lower main surfaces is formed of a photocurable resin, The body can be formed in a short time, and the mass productivity of the multilayer wiring board is significantly improved.

According to the multilayer wiring board of the present invention, the photocurable resin is cured by light irradiation, and the volume of the photocurable resin hardly decreases during curing. As a result, even if the organic resin insulating layers and the thin film wiring conductors are alternately arranged on the upper and lower surfaces of the insulating substrate to form a multilayer wiring portion, the organic resin insulating layers are all flattened. There is no occurrence of disconnection or the like in the thin film wiring conductor formed on the organic resin insulating layer.

Further, according to the multilayer wiring board of the present invention, since the wiring is formed on the insulating substrate by the thin film forming technique, the wiring can be miniaturized, and the wiring can be formed at an extremely high density.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a multilayer wiring board of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating substrate 2 ... Organic resin insulating layer 3 ... Thin film wiring conductor 4 ... Multilayer wiring part 5 ... Through-hole 6 ... Conductive layer 7 ... Organic resin filler

Claims (3)

[Claims] An insulating substrate having a through hole penetrating both upper and lower main surfaces, a conductive layer extending from an upper surface of the insulating substrate to a lower surface via an inner wall of the through hole, and an organic resin filled in the through hole The filler is attached on at least one main surface of the insulating substrate, and the organic resin insulating layers and the thin film wiring conductors are alternately arranged, and a part of the thin film wiring conductor is electrically connected to the conductive layer. A multilayer wiring board comprising: a multilayer wiring portion, wherein the organic resin filler is formed of a photocurable resin. 2. The multilayer wiring board according to claim 1, wherein a filler having a particle size of 0.01 μm to 10 μm is contained in the organic resin filler made of the photocurable resin. 3. The organic resin filler 1 according to claim 1, wherein
3. The multilayer wiring board according to claim 2, wherein the amount is 10 to 80 parts by weight with respect to 00 parts by weight.