JPH1197848A - Multilayered wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable multilayered wiring board, in which a conductive layer provided in a board is electrically, reliably and firmly con nected to a thin-film wiring conductor layer via a through-hole conductor. SOLUTION: In a multilayered wiring board, in which an organic resin insulation layer 2 and a thin film wiring conductor layer 3 are alternately laminated in a multilayer on a board 1 having a conductive layer 6 to form a multilayered wiring part 4, and also the conductive layer 6 is connected to the thin-film wiring conductor layers 3 via a through-hole conductor 9 adhering to an inner wall face of a through-hole 8 provided in the organic resin insulation layer 2, the through-hole 8 provided in the organic resin insulation layer 2 has an opening diameter on a lower face side which is set larger than an opening diameter on an upper face side.

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-shaped metal paste is printed and applied on the outer surface of the green ceramic body in a predetermined pattern by a screen printing method. Then, a plurality of these 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.

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 a nitride having an oxide film deposited on the surface. Non-oxide ceramics such as an aluminum 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 multilayer wiring board formed at a high density by using a thin film forming technique capable of miniaturization instead of forming a part of the wiring conductor by the conventional thick film forming technique has been proposed. It has been adopted. Such a multilayer wiring board is made of an insulating material made of glass epoxy resin or the like formed by impregnating a ceramic made of an aluminum oxide sintered body or the like having through-holes penetrating on both upper and lower surfaces or a cloth woven with glass fibers with an epoxy resin. A substrate, a conductive layer made of a metal material such as copper derived from the upper surface of the insulating substrate to the lower surface via the inner wall of the through-hole, and an organic resin made of an epoxy resin or the like, which is adhered on at least one main surface of the insulating substrate. An insulating layer and a thin-film wiring conductor layer made of a metal such as copper or aluminum are alternately laminated in multiple layers, and a part of the thin-film wiring conductor layer is formed on the inner wall surface of a through hole provided in the organic resin insulating layer in the conductive layer. And a multi-layer wiring portion connected via a through-hole conductor attached to the thin-film wiring conductor layer of the multi-layer wiring portion via a conductive layer. Or connect to, so as to electrically connect the thin film wiring conductor layers to each other in the multilayer wiring portion is deposited on the upper and lower surfaces of the insulating substrate.

[0007] 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 or the like, and processing this into a predetermined pattern by a photolithography technique. A conductive layer extending from the upper surface of the substrate to the lower surface via the inner wall of the through-hole is adhered, and then an organic resin such as an epoxy resin formed on the upper and / or lower surface of the insulating substrate by a spin coating method, a thermosetting treatment, or the like. A multi-layered wiring section is formed by alternately laminating an insulating layer made of and a thin-film wiring conductor layer formed by employing a thin film forming technique such as electroless plating and a photolithography technique on a metal such as copper or aluminum. It is made by doing.

The conductive layer and the thin-film wiring conductor layer formed on the insulating substrate are electrically connected to each other via a through-hole conductor attached to the inner wall surface of the through-hole provided in the organic resin insulating layer. The through holes formed in the organic resin insulating layer are formed by applying a resist material on the organic resin insulating layer and exposing and developing the resist material to form a window having a predetermined shape at a predetermined position. An etchant is placed in the window of the material, the organic resin insulating layer located in the window of the resist material is removed, a hole (through hole) is formed in the organic resin insulating layer, and finally, the resist material is coated with an organic resin. The through-hole conductor, which is formed by peeling and removing the insulating layer from the insulating layer and adhered to the inner wall surface of the through hole, is formed by, for example, applying copper or the like to the inner wall surface of the through hole by electroless plating. It is formed by.

[0009]

However, in this multilayer wiring board, the through-holes are perpendicular to the organic resin insulating layer, or the opening diameter on the lower surface side of the organic resin insulating layer is larger than the opening diameter on the upper surface side. Is also formed in a narrow mortar shape, so if a through-hole conductor is deposited on the inner wall surface of the through-hole, the junction between the through-hole conductor and the conductive layer deposited on the insulating substrate becomes narrow, As a result, a drawback that the electrical connection between the conductive layer formed on the insulating substrate and the thin-film wiring conductor layer via the through-hole conductor becomes low in reliability was induced. In particular, when a fine foreign matter having a particle size of about 5 to 30 μm enters the through hole,
There is a disadvantage that the electrical connection between the through-hole conductor and the conductive layer is completely broken by the foreign matter.

In this multilayer wiring board, when a through hole is formed in the organic resin insulating layer, a portion of the organic resin insulating layer is likely to remain below the through hole, and the remaining organic resin insulating layer is partially removed. There is also a drawback that the formation of the through-hole conductor is hindered, and the reliability of the electrical connection between the through-hole conductor and the conductive layer deteriorates.

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 reliable and robust electrical connection between a conductive layer provided on a substrate and a thin-film wiring conductor layer via a through-hole conductor. Another object of the present invention is to provide a highly reliable multilayer wiring board.

[0012]

According to the present invention, there is provided a multilayer wiring portion comprising an organic resin insulating layer and a thin film wiring conductor layer alternately laminated on a substrate having a conductive layer. A multilayer wiring board comprising a thin-film wiring conductor layer and a through-hole conductor attached to an inner wall surface of a through-hole provided in an organic resin insulating layer, wherein the through-hole provided in the organic resin insulating layer is provided. The hole is characterized in that the opening diameter on the lower surface side is larger than the opening diameter on the upper surface side.

Further, according to the present invention, the inner wall surface of the through hole may be formed at an angle of 60 ° to 8 °
It is characterized by having an inclination of 0 °.

According to the multilayer wiring board of the present invention, the opening diameter of the through hole provided in the organic resin insulating layer is made larger on the lower surface side and smaller on the upper surface side, so that the through hole conductor is formed on the inner wall surface of the through hole. In the case where the through-hole conductor is formed, the through-hole conductor and the conductive layer disposed under the through-hole conductor are bonded over a wide area, and the bonding between the two is strengthened. As a result, the conductive layer formed on the substrate and the thin-film wiring conductor layer are bonded together. The electric connection through the through-hole conductor is reliably and firmly performed, and the reliability can be increased. In particular, even if a fine foreign matter having a particle size of about 5 to 30 μm enters the through hole, the through hole conductor and the conductive layer disposed thereunder are bonded over a wide area, so that the foreign matter joins the two. The electrical connection between the conductive layer and the thin-film wiring conductive layer formed on the substrate can be more reliably and firmly established through the through-hole conductor. it can.

According to the multilayer wiring board of the present invention, the opening diameter of the through hole provided in the organic resin insulating layer is made larger on the lower surface side and smaller on the upper surface side. Part of the conductive layer and the thin-film wiring conductor layer through the through-hole conductor attached to the inner wall surface of the through-hole to ensure high reliability. Can be.

[0016]

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 a substrate, 2 is an organic resin insulating layer, and 3 is a thin-film wiring conductor layer.

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

The substrate 1 is made of an oxide ceramic such as an aluminum oxide sintered body or a mullite sintered body, or a non-conductive body such as an aluminum nitride sintered body or a silicon carbide sintered body having an oxide film on its surface. Oxide ceramics, and further made of an electrically insulating material such as glass epoxy resin impregnated with epoxy resin in a cloth woven with glass fiber, for example, when formed of aluminum oxide sintered body By adding an appropriate organic solvent and a solvent to raw material powders such as aluminum oxide, silicon oxide, magnesium oxide and calcium oxide and mixing them to form a slurry, and employing a conventionally known doctor blade method or calendar roll method, A ceramic green sheet (ceramic green sheet) is formed, and then the ceramic green sheet is appropriately punched. The raw material powder is processed and formed into a predetermined shape and fired at a high temperature (about 1600 ° C.), or a raw material powder such as aluminum oxide is mixed with a suitable organic solvent and a solvent to prepare the raw material powder. It is manufactured by molding into a predetermined shape by a press molding machine, and finally by firing the molded body at a temperature of about 1600 ° C. When it is made of glass epoxy resin, for example, epoxy resin is added to a cloth woven with glass fiber. And the epoxy resin precursor is thermoset at a predetermined temperature.

The substrate 1 has a through hole 5 having a diameter of, for example, 0.2 mm to 1.0 mm penetrating through the upper and lower surfaces.
Are formed on the inner wall of the through hole 5 at both ends.
Conducting layers 6 are attached to both upper and lower surfaces of the substrate.

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

Further, a conductive layer 6 is formed on the inner wall of the through hole 5 and on both upper and lower surfaces of the substrate 1.
Is made of a metal material such as nickel or copper. For example, in the case of being formed of nickel, the substrate 1 having the through-holes 5 is made of nickel sulfate 40 g / l, sodium citrate 24 g / l, and sodium acetate 14 g. / L, 20 g / L of sodium hypophosphite, 5 g / L of ammonium chloride, and depositing a nickel layer having a thickness of 1 μm to 40 μm using an electroless plating bath, and then etching the nickel layer By processing into a predetermined pattern by the method, both ends are led out to the upper and lower surfaces of the substrate 1 on the inner wall of the through hole 5 so as to be adhered.

The conductive layer 6 electrically connects the thin film wiring conductor layer 3 of the multilayer wiring portion 4 provided on the main surface of the substrate 1 to an external electric circuit, or is provided on both upper and lower surfaces of the substrate 1. It functions to electrically connect the thin film wiring conductor layers 3 of each multilayer wiring part 4 to each other.

The through hole 5 formed in the substrate 1 is filled with an organic resin filler 7 made of epoxy resin or the like, 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 attached to the upper and lower main surfaces of the substrate 1.

The organic resin filler 7 is used when forming a multilayer wiring portion 4 comprising an organic resin insulating layer 2 and a thin film wiring conductor layer 3 on the upper surface and / or lower surface of the substrate 1 as described later. It functions to maintain the flatness of the resin insulating layer 2 and the thin-film wiring conductor layer 3.

The organic resin filler 7 fills the through hole 5 of the substrate 1 with a precursor such as an epoxy resin, and then is applied with a temperature of 80 to 200 ° C. for 0.5 to 3 hours. Is completely cured by heat so that the through holes 5 of the substrate 1 are formed.
Is filled in.

Further, the substrate 1 has a multilayer wiring portion 4 formed by alternately laminating an organic resin insulating layer 2 and a thin film wiring conductor layer 3 on the upper surface thereof to form a multilayer wiring portion 4.
Are electrically connected to the conductive layer 6.

The organic resin insulating layer 2 constituting the multilayer wiring portion 4 functions to electrically insulate the thin film wiring conductor layers 3 located above and below, and the thin film wiring conductor layer 3 is used to transmit electric signals. Acts as a road.

The organic resin insulating layer 2 of the multilayer wiring section 4
Made of photosensitive or thermosetting epoxy resin, bismaleimide triazine resin, polyphenylene ether resin, fluororesin, etc.For example, when it is made of an acid-catalyzed photosensitive epoxy resin, phenol novolak resin, methylol melamine, diallyl Addition and mixing of propylene glycol monomethyl ether acetate to a diazonium salt to obtain an acid-catalyzed photosensitive epoxy resin precursor in paste form, and spin-coating the acid-catalyzed photosensitive epoxy resin precursor on the top of the substrate 1 And a predetermined thickness by a doctor blade method, and then subject it to a predetermined exposure at an energy of 1 to ³ J / cm ³ by an exposure machine using a high-pressure mercury lamp or the like, and photo-curing and spraying a predetermined area. Develop with a developing machine etc.
The hole is formed by heating at a temperature of 180 ° C. for 30 to 60 minutes to completely cure the hole.

Further, a through hole 8 is formed in each of the organic resin insulating layers 2 of the multilayer wiring section 4, and the through holes 8 are formed between the conductive layer 6 formed on the substrate 1 and the thin film wiring conductor layer 3. And electrically serves as a connection path for electrically connecting each of the thin film wiring conductor layers 3 located above and below with the organic resin insulating layer 2 interposed therebetween.

The through hole 8 is formed by applying a resist material having a window to the organic resin insulating layer 2 and etching the organic resin insulating layer 2 located at the window of the resist material. In the case where is formed of a photosensitive organic resin, the photosensitive organic resin precursor is formed by providing an unexposed region in a portion when the photosensitive organic resin precursor is subjected to an exposure treatment and photocured. When the layer 2 is formed of a photosensitive organic resin such as a photosensitive epoxy resin, when the organic resin insulating layer 2 is formed as described above, for example, an acid-catalyzed photosensitive epoxy applied to the upper portion of the substrate 1 is used. A predetermined region of the resin precursor is exposed to light to directly form the organic resin insulating layer 2, and a resist material for forming the through hole 8 in the organic resin insulating layer 2 is separately prepared. In short absolutely no, this makes it possible to form a multilayer wiring board as a product cheaper it becomes possible to easily form the through-hole 5 in the organic resin insulating layer 2. Therefore, it is preferable that the organic resin insulating layer 2 is formed of a photocurable organic resin.

Each of the organic resin insulating layers 2 has a thin-film wiring conductor layer 3 having a predetermined pattern on its upper surface, and a through-hole conductor 9 on the inner wall of a through-hole 8 provided in each organic resin insulating layer 2. The conductive layer 6 and the thin-film wiring conductor layer 3 formed on the substrate 1 by the through-hole conductor 9, and each of the thin-film wiring conductor layers 3 positioned above and below the organic resin insulating layer 2 therebetween. It is designed to be electrically connected.

The thin-film wiring conductor layer 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. It is formed by employing a thin film forming technique such as an electrolytic plating method, a vapor deposition method, and a sputtering method, and an etching technique. For example, when it is formed of copper, the upper surface of the organic resin insulating layer 2 and the through hole 8 are formed. Copper sulfate 0.06 mol / l, formalin 0.3 mol / l, sodium hydroxide 0.3 on inner wall
Using an electroless copper plating bath consisting of 5 mol / l and 0.35 mol / l ethylenediaminetetraacetic acid, a thickness of 1
A copper layer having a thickness of 40 μm to 40 μm is deposited, and then the copper layer is processed into a predetermined pattern by employing an etching technique, thereby forming a through hole between each organic resin insulating layer 2 and each organic resin insulating layer 2. 8 is arranged on the inner wall.
In this case, since the thin-film wiring conductor layer 3 is formed by a thin-film forming technique, it is possible to miniaturize the wiring, thereby making it possible to form the thin-film wiring conductor layer 3 at an extremely high density.

Further, among the through holes 8 provided in the organic resin insulating layer 2 of the multilayer wiring section 4, at least the through hole 8 provided in the lowermost organic resin insulating layer 2 has a larger opening diameter on the lower surface side. When the through-hole conductor 9 is attached to the inner wall surface of the through-hole 8, the through-hole conductor 9 and the conductive layer 6 formed below are wide. In this case, the electric connection between the conductive layer 6 formed on the substrate 1 and the thin-film wiring conductor layer 3 via the through-hole conductor 9 is reliably and firmly made. High reliability can be achieved. In particular, even if fine foreign matter having a particle size of about 5 to 30 μm enters the through hole 8, the through hole conductor 9 and the conductive layer 6 disposed under the through hole conductor 9 are bonded to each other over a wide area. The electrical connection between the two is maintained without impeding the joining of the two, thereby improving the electrical connection between the conductive layer 6 formed on the substrate 1 and the thin-film wiring conductor layer 3 via the through-hole conductor 9. We can make sure and strong.

When the organic resin insulating layer 2 is formed of a photosensitive epoxy resin, the through-hole 8 having a large opening diameter on the lower surface side and a small opening diameter on the upper surface side is formed of a photosensitive epoxy resin applied on the upper portion of the substrate 1. The precursor is formed by controlling exposure conditions. In this case, the through hole 8 provided in the organic resin insulating layer 2 has a larger opening diameter on the lower surface side and a smaller opening diameter on the upper surface side. Thus, the electrical connection between the conductive layer 6 and the thin-film wiring conductor layer 3 via the through-hole conductor 9 attached to the inner wall surface of the through-hole 8 can be made highly reliable. .

When the angle θ between the inner wall surface and the lower surface of the organic resin insulating layer 2 satisfies 60 °> θ, the inner wall surface of the through hole 8 formed in the organic resin insulating layer 2 is formed. It tends to be difficult to apply the through-hole conductor 9 to a uniform thickness on the other hand, and when 80 ° <θ, the bonding area between the through-hole conductor 9 and the lower thin-film wiring conductor layer 3 is reduced, and both are reduced. It tends to be difficult to make a firm bond. Therefore, the through hole 8 formed in the organic resin insulating layer 2 is formed between the inner wall surface and the organic resin insulating layer 2.
It is preferable that the angle θ formed by the lower surface of the substrate be 60 ° ≦ θ ≦ 80 °.

Further, when the thickness of each of the organic resin insulating layers 2 having the through holes 8 exceeds 100 μm, the photosensitive epoxy resin precursor is exposed to light and developed to form holes that become the through holes 8. When the through hole 8 is formed by using photolithography technology in the organic resin insulating layer 2, the spread of light and the processing time for etching become longer, so that the through hole 8 is formed into a desired sharp shape. Becomes difficult, and 5
When the thickness is less than μm, unnecessary holes are formed in the organic resin insulating layer 2 when roughening is performed on the upper surface of the organic resin insulating layer 2 to increase the bonding strength of the organic resin insulating layer 2 located above and below.
There is a risk that unnecessary electrical short circuits may be caused in the thin film wiring conductor layers 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, when the thickness of each thin-film wiring conductor layer 3 of the multilayer wiring portion 4 is less than 1 μm, the electric resistance of each thin-film wiring conductor layer 3 becomes large and a predetermined value is applied to each thin-film wiring conductor layer 3. It is difficult to transmit an electric signal. If the thickness exceeds 40 μm, a large stress is present in the thin-film wiring conductor layer 3 when the thin-film wiring conductor layer 3 is applied to the organic resin insulating layer 2. As a result, the thin film wiring conductor layer 3 is easily peeled off from the organic resin insulating layer 2. Therefore, the thickness of each thin-film wiring conductor layer 3 of the multilayer wiring section 4 is 1
It is preferable to set it in the range of μm to 40 μm.

Thus, according to the multilayer wiring board of the present invention, electronic components such as semiconductor elements, capacitance elements, resistors and the like are mounted and mounted on the multilayer wiring section 4 attached to the upper surface of the substrate 1.
By electrically connecting the electrodes of the electronic component to the thin-film wiring conductor layer 3, a semiconductor device or a hybrid integrated circuit device is obtained. If the conductive layer 6 formed on the substrate 1 is connected to an external electric circuit, the semiconductor device or the hybrid integrated circuit device can be obtained. The integrated circuit device is electrically connected to an external electric circuit.

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 gist of the present invention. Although the multilayer wiring portion 4 including the organic resin insulating layer 2 and the thin film wiring conductor layer 3 is provided only on the upper surface, the multilayer wiring portion 4 may be provided only on the lower surface side of the substrate 1 or on both upper and lower surfaces. .

[0040]

According to the multilayer wiring board of the present invention, the opening diameter of the through hole provided in the organic resin insulating layer is made larger on the lower surface side and smaller on the upper surface side. When a conductor is formed, the through-hole conductor and the conductive layer disposed under the through-hole conductor are joined over a large area, so that the joint between the two is strengthened. As a result, the conductive layer formed on the substrate and the thin-film wiring conductor The electrical connection with the layer via the through-hole conductor is reliable and strong, and high reliability can be achieved. In particular, even if a fine foreign matter having a particle size of about 5 to 30 μm enters the through hole, the through hole conductor and the conductive layer disposed thereunder are bonded over a wide area, so that the foreign matter joins the two. The electrical connection between the conductive layer and the thin-film wiring conductive layer formed on the substrate can be more reliably and firmly established through the through-hole conductor. it can.

According to the multilayer wiring board of the present invention, the opening diameter of the through hole provided in the organic resin insulating layer is made larger on the lower surface side and smaller on the upper surface side. Part of the conductive layer and the thin-film wiring conductor layer through the through-hole conductor attached to the inner wall surface of the through-hole to ensure high reliability. Can be.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Organic resin insulating layer 3 ... Thin film wiring conductor layer 4 ... Multilayer wiring part 6 ... Conductive layer 8 ... Through hole 9 ...・ Through-hole conductor

Claims (2)

[Claims] A multilayer wiring portion comprising an organic resin insulating layer and a thin-film wiring conductor layer alternately laminated in a multilayer on a substrate having a conductive layer, and the conductive layer and the thin-film wiring conductor layer are formed of an organic resin. A multilayer wiring board connected through a through-hole conductor attached to an inner wall surface of a through-hole provided in an insulating layer, wherein the through-hole provided in the organic resin insulating layer has an opening diameter on a lower surface side. A multilayer wiring board characterized by being larger than an opening diameter on an upper surface side. 2. The inner wall surface of the through hole according to claim 1, wherein the inner wall surface and the lower surface of the organic resin insulating layer are inclined at an angle of 60 ° to 80 °. Multilayer wiring board.