JPH11233679A - Multilayer wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer wiring board whereon wiring conductors are formed by the thin-film formation technique to enable the forming of a wiring conductors at a high density, and the connection reliability of components such as semiconductor elements or capacitance elements to a thin-film wiring conductor layer can be made high, by strengthening the bond of bonding pads with respect to an org. resin insulation layer. SOLUTION: This multilayer wiring board is constituted, such that org. resin insulation layers 2 and thin film wiring conductor layers 3 are laminated alternately on a board 1, the thin-film wiring conductor layers 3 located above and below are connected electrically via through-hole conductors 9 formed on the inner walls of through-holes 8 provided at the org. resin insulation layer 2, and bonding pads 7 which are electrically connected to thin film wiring conductor layers 3 and provided on bottom faces of holes 10 are provided at the uppermost org. resin insulation layer 2a, and an external electronic component A are connected to the pads 7. At least a part of the lower end of the hole 10 inner wall is embedded in the bonding pad 7.

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 Hitherto, a multilayer wiring board used in 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 printed and applied in a predetermined pattern on the outer surface of a sheet-like green ceramic body by a screen printing method, and then a plurality of these are laminated and fired in a reducing atmosphere. A method of sintering and integrating a high melting point 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 using a thin film forming technique capable of miniaturization instead of forming a wiring conductor by a conventionally known thick film forming technique is used. It has become.

A multilayer wiring board in which such wiring conductors are formed by a thin film forming technique is made of glass epoxy resin formed by impregnating ceramics made of aluminum oxide sintered body or glass cloth woven with glass fibers with epoxy resin. An insulating layer made of an organic resin such as an epoxy resin formed by spin coating and thermosetting on the upper surface of a substrate made of a metal, such as copper or aluminum, and a thin film forming technique such as an electroless plating method or a vapor deposition method, and photolithography. A structure in which thin-film wiring conductor layers formed by adopting technology are alternately laminated, and the thin-film wiring conductor layers located above and below are electrically connected via through-hole conductors provided in the organic resin insulating layer. Bonding on the upper surface of the uppermost organic resin insulating layer to be electrically connected to the thin film wiring conductor layer Previously formed the head, so as to connect the active components and capacitive elements such as semiconductor devices to the bonding pad, the passive components of the electrode of the resistor or the like through a solder or the like brazing material.

[0008]

However, in a multilayer wiring board formed by alternately laminating the organic resin insulating layers and the thin film wiring conductor layers in multiple layers, each of the bonding pads has the uppermost organic resin insulating layer. The electrodes are formed on the same plane on the top surface, and the electrodes of active components such as semiconductor elements, capacitors, and passive components such as resistors are connected to the bonding pads from solder etc. because the adjacent distance between the bonding pads is extremely narrow, for example, 200 μm. When the connection is made via the brazing material, a part of the brazing material flows to the adjacent bonding pad and electrically short-circuits the adjacent bonding pad. It has the disadvantage of causing malfunction.

Further, since the bonding of the bonding pad to the organic resin insulating layer is planar, the coefficient of thermal expansion between the multilayer wiring board and the semiconductor element, the capacitor, the resistor, etc. is formed at the bonding portion between the organic resin insulating layer and the bonding pad. When the thermal stress generated due to the difference is applied repeatedly, the bonding pad is peeled off from the organic resin insulating layer, and as a result, the thin film of the active component such as the semiconductor device and the passive component such as the capacitor and the resistor. There was also a disadvantage that the reliability of connection to the wiring conductor layer was low.

The present invention has been made in view of the above-mentioned drawbacks, and its object is to form a wiring conductor by a thin film forming technique,
To enable the formation of wiring conductors at high density and to strengthen the bonding of the bonding pads to the organic resin insulating layer to achieve high reliability of connection of semiconductor elements, capacitors and other components to the thin film wiring conductor layer. It is an object of the present invention to provide a multilayer wiring board that can perform the above.

[0011]

According to the present invention, there is provided a through-hole in which an organic resin insulating layer and a thin film wiring conductor layer are alternately laminated on a substrate, and thin film wiring conductor layers positioned above and below are provided on the organic resin insulating layer. A bonding pad electrically connected via a hole conductor, and a bottom surface of a hole provided in the uppermost organic resin insulating layer, electrically connected to the thin film wiring conductor layer and connected to an external electronic component. Wherein at least a part of a lower end side of the inner wall of the hole is embedded in a bonding pad.

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 a very high density.

According to the multilayer wiring board of the present invention, since a hole is provided in the uppermost organic resin insulating layer and a bonding pad is formed on the bottom of the hole, the distance between adjacent bonding pads is substantially reduced. As a result, when connecting the electrodes of active components such as semiconductor elements, capacitors, and passive components such as resistors to the bonding pad via a brazing material made of solder or the like, a part of the brazing material is adjacent to the bonding pad. The electrodes such as the semiconductor elements can be accurately and electrically connected to the predetermined bonding pads without flowing to the pads, and the semiconductor elements and the like can always be normally operated.

Further, according to the multilayer wiring board of the present invention, at least a part of the lower end side of the inner wall of the hole formed in the uppermost organic resin insulating layer is buried in the bonding pad. And the uppermost organic resin insulating layer are bonded very firmly, and the thermal stress generated due to the difference in the thermal expansion coefficient between the organic resin insulating layer and the semiconductor element, capacitor element, etc. is repeatedly applied to the joint between them. The bonding pad does not peel off from the organic resin insulating layer even if it is done, which makes the connection reliability of the active components such as semiconductor devices and the passive components such as capacitors and resistors to the thin film wiring conductor layer extremely high. Can be made.

[0015]

Next, the present invention will be described in detail with reference to the accompanying drawings. 1 and 2 show an embodiment of the multilayer wiring board of the present invention, wherein 1 is a substrate, 2 is an organic resin insulating layer,
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 material 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 materials 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 calender roll method, A ceramic green sheet (ceramic green sheet) is formed, and then a suitable punch is formed on the ceramic green sheet. By baking at a high temperature (about 1600 ° C.) with can process the applied and forms a predetermined shape,
Alternatively, a raw material powder such as aluminum oxide is mixed with a suitable organic solvent and a solvent to prepare the raw material powder, and the raw material powder is formed into a predetermined shape by a press molding machine. Finally, the formed body is heated to a temperature of about 1600 ° C. In the case of being manufactured by baking with, and made of glass epoxy resin, for example, impregnating an epoxy resin precursor into a cloth woven of glass fiber and thermally curing the epoxy resin precursor at a predetermined temperature Produced by

The substrate 1 is formed with through holes 5 having a hole diameter of, for example, 300 μm to 500 μm, which penetrate the upper and lower surfaces of the substrate 1. A conductive layer 6 is applied.

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 the multilayer wiring portion is formed on both upper and lower surfaces of the substrate 1. When the substrate 4 is provided, it functions as a forming hole for forming the conductive layer 6 for electrically connecting the thin film wiring conductor layers of the multilayer wiring portion 4 on both surfaces, and the substrate 1 is subjected to a drilling method. Thus, a predetermined shape is formed at a predetermined position on the substrate 1.

The conductive layer 6 formed on the inner wall of the through hole 5 and on the upper and lower surfaces of the substrate 1 is made of a metal material such as copper or nickel, for example, and employs well-known plating and etching methods. As a result, it is formed on the inner wall of the through hole 5 with both ends being led out to the upper and lower surfaces of the substrate 1.

On the upper surface of the substrate 1, a multilayer wiring portion 4 formed by alternately arranging an organic resin insulating layer 2 and a thin film wiring conductor layer 3 in multiple layers is attached. 4
The organic resin insulating layer 2 has the function of electrically insulating the upper and lower thin film wiring conductor layers 3, and the thin film wiring conductor layer 3 functions as a transmission path for transmitting electric signals.

The organic resin insulating layer 2 of the multilayer wiring section 4
It is made of an organic resin such as an epoxy resin, a bismaleimide triazine resin, a polyphenylene ether resin, and a fluororesin. For example, when the resin is made of an epoxy resin, it is amine-cured to a bisphenol A type epoxy resin, a novolak type epoxy resin, a glycidyl ester type epoxy resin, or the like. A curing agent such as a curing agent, an imidazole-based curing agent, an acid anhydride-based curing agent is added and mixed to obtain a paste-like epoxy resin precursor, and the epoxy resin precursor is adhered to the upper portion of the substrate 1 by spin coating. After that, this is brought to 80 ° C. to 200 ° C.
The film is formed by heat-treating with heat of 0.5 ° C. for 0.5 to 3 hours and heat-curing.

Further, the organic resin insulating layer 2 of the multilayer wiring section 4
Has a through hole 8 having a minimum diameter of about 1.5 times the thickness of the organic resin insulating layer 2 at each predetermined position.
, And acts as a forming hole for forming a through-hole conductor 9 for electrically connecting each of the thin-film wiring conductor layers 3 located above and below via.

The through hole 8 provided in the organic resin insulating layer 2 is formed in the organic resin insulating layer 2 to a predetermined diameter by employing a conventionally known photolithography technique.

A thin-film wiring conductor layer 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 conductor layers 3 located above and below the organic resin insulating layer 2 with the through-hole conductor 9 therebetween is electrically connected.

The thin-film wiring conductor layer 3 and the through-hole conductor layer 9 provided on the upper surface of each of the organic resin insulating layers 2 and the inner wall of the through-hole 8 are formed by electroless plating a metal material such as copper, nickel, gold, or aluminum. It is formed by adopting a thin film forming technique such as a sputtering method, a vapor deposition method, and a sputtering method, and a photolithography technique. For example, when it is formed of copper, the upper surface of the organic resin insulating layer 2 and the inner surface of the through hole 8 are formed. In addition, copper sulfate 0.06 mol / l, formalin 0.3 mol / l, sodium hydroxide 0.3
Using an electroless copper plating bath consisting of 5 mol / l and 0.35 mol / l of 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 photolithography to be disposed between the organic resin insulating layers 2 and on the inner wall of the through hole 8. In this case, the thin film wiring conductor layer 3
In addition, since the through-hole conductor 9 is formed by a thin-film forming technique, it is possible to miniaturize the wiring, whereby the thin-film wiring conductor layer 3 can be formed at an extremely high density.

The multilayer wiring portion 4 formed by alternately arranging the organic resin insulating layers 2 and the thin film wiring conductor layers 3 in a multilayer structure has a center line average roughness (upper surface) of each organic resin insulating layer 2. R
By setting a rough surface of 0.05 μm ≦ Ra ≦ 5 μm in a), the bonding between the organic resin insulating layer 2 and the thin-film wiring conductor layer 3 and the bonding between the organic resin insulating layers 2 located above and below can be made strong. . Therefore, the upper surface of each organic resin insulating layer 2 of the multilayer wiring portion 4 is roughened by an etching method or the like,
Center line average roughness (Ra): 0.05 μm ≦ Ra ≦ 5 μm
It is preferable to make the surface rough.

The count value of the height (Pc) of the unevenness at a length of 2.5 mm on the surface of the organic resin insulating layer 2 is 500 or more for 1 μm ≦ Pc ≦ 10 μm.
2500 μm of 1 μm ≦ Pc ≦ 1 μm, 0.01 μm
If ≦ Pc ≦ 0.1 μm is set to 12,500 or more, the bonding between the organic resin insulating layer 2 and the thin-film wiring conductor layer 3 and the bonding between the organic resin insulating layers 2 located above and below become stronger. Therefore, the organic resin insulating layer 2 has a thickness of 2.5
The count value of the height (Pc) of the unevenness in the length of mm is 1 μm ≦ Pc ≦ 10 μm.
2500 or more m ≦ Pc ≦ 1 μm, 0.01 μm ≦ P
It is preferable that c ≦ 0.1 μm is set to 12,500 or more.

The count value of the center line average roughness (Ra) of the upper surface of the organic resin insulating layer 2 and the height of the unevenness (Pc) at a length of 2.5 mm are obtained by measuring the surface of the organic resin insulating layer 2 with an atomic force. Microscope (Dimensio manufactured by Digital Instruments Inc.
n 3000-Nano Scope III) 50μm diagonal (70μm)
m), the surface condition was inspected and measured, and each numerical value was obtained from the measurement result.

The center line average roughness (Ra) is 0.0
5 μm ≦ Ra ≦ 5 μm, the count value of the height of unevenness (Pc) at a length of 2.5 mm is 1 μm ≦ Pc ≦ 10 μm
m is 500 or more, and 0.1 μm ≦ Pc ≦ 1 μm is 250
0 or more, 0.01 μm ≦ Pc ≦ 0.1 μm is 1250
The surface of the zero or more organic resin insulating layers 2 is roughened to a predetermined roughness by spraying a gas such as CHF ₃ , CF ₄ , Ar or the like on the upper surface of the organic resin insulating layers 2 or performing active ion etching. You.

Further, when the thickness of each of the organic resin insulating layers 2 exceeds 100 μm, when the through holes 8 are formed by employing photolithography technology in the organic resin insulating layers 2, the etching processing time becomes longer and the It is difficult to form the hole 8 into a desired clear shape, and if it is less than 5 μm, rough surface processing is performed on the upper surface of the organic resin insulating layer 2 to increase the bonding strength of the upper and lower organic resin insulating layers 2. In this case, there is a risk that unnecessary holes are formed in the organic resin insulating layer 2 and unnecessary electrical short circuits are caused in the thin film wiring conductor layers 3 located above and below. Therefore, the organic resin insulating layer 2 has a thickness of 5 μm to 100 μm.
It is preferable to keep the range of 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 the electric signal of
When the thickness exceeds 40 μm, a large stress is present inside the thin film wiring conductor layer 3 when the thin film wiring conductor layer 3 is adhered to the organic resin insulating layer 2, and the large intrinsic stress causes the thin film wiring conductor layer 3 to cause an organic resin insulation. It is easier to peel off than the layer 2.
Therefore, it is preferable that the thickness of each thin-film wiring conductor layer 3 of the multilayer wiring portion 4 be in the range of 1 μm to 40 μm.

The organic resin insulating layer 2 and the thin film wiring conductor layer 3
The multilayer wiring portion 4 formed by alternately laminating the layers is further provided with a hole 10 in the uppermost organic resin insulating layer 2a. A bonding pad 7 is formed which is electrically connected to the bonding pad 7.

The hole 10 formed in the uppermost organic resin insulating layer 2a functions as a forming hole for forming a bonding pad 7 having an electrical connection to the thin film wiring conductor layer 3, and the uppermost organic resin insulating layer 2a serves as a forming hole. The resin insulating layer 2a is formed at a predetermined position with a predetermined opening diameter by employing a conventionally known photolithography technique.

The bonding pad 7 formed on the bottom surface of the hole 10 provided in the uppermost organic resin insulating layer 2a connects the electrode of the electronic component A such as a semiconductor element or a capacitor to the thin film wiring conductor layer 3. Each electrode of the electronic component A is connected to the bonding pad 7 by brazing via a brazing material such as solder. In this case, the bonding pads 7 are formed on the bottom surface of the hole 10 even if the distance between adjacent bonding pads is as narrow as about 200 μm, so that the distance between the adjacent bonding pads 7 becomes substantially longer. A part of the brazing material for connecting the bonding pad 7 to an electrode of the electronic component A, such as a semiconductor element or a capacitor, does not flow to the adjacent bonding pad 7, and the electronic component A
The electronic components A such as semiconductor elements can always be normally operated by electrically connecting these electrodes accurately.

The bonding pad 7 is made of, for example, the same metal material as the thin-film wiring conductor layer 3, specifically, a metal material such as copper, nickel, gold, aluminum or the like. Hole 1 by the same method
0 is formed on the bottom surface.

As shown in FIG. 2, the lower end side of the inner wall of the hole 10 provided in the uppermost organic resin insulating layer 2a is buried inside the bonding pad 7.

When the lower end of the inner wall of the hole 10 provided in the uppermost organic resin insulating layer 2a is buried inside the bonding pad 7, the bonding pad 7 and the uppermost organic resin insulating layer 2a become extremely strong. The heat generated due to the difference in the coefficient of thermal expansion between the organic resin insulating layer 2a and the electronic component A such as a semiconductor element is formed at the joint between the bonding pad 7 and the uppermost organic resin insulating layer 2a. Even if stress is repeatedly applied, the bonding pad 7 does not peel off from the organic resin insulating layer 2a, and the reliability of connection of the electronic component A to the thin film wiring conductor layer can be made extremely high.

As a method of embedding the lower end of the inner wall of the hole 10 provided in the uppermost organic resin insulating layer 2a inside the bonding pad 7, for example, the inner wall of the hole 10 may be formed in a mortar shape. This is performed by forming a slightly thicker bonding pad 7 on the bottom surface of the hole 10.

It is not necessary to embed the entire periphery of the lower end side of the inner wall of the hole 10 inside the bonding pad 7, but it is sufficient to embed a part thereof inside the bonding pad 7.

Thus, according to the multilayer wiring board of the present invention, the electrodes of the electronic component A such as a semiconductor element and a capacitor are soldered to the bonding pads 7 provided on the uppermost organic resin insulating layer 2a. Electronic component A
Are electrically connected to the thin-film wiring conductor layer 3 via the bonding pads 7 to form a semiconductor device or a hybrid integrated circuit device. If a part of the thin-film wiring conductor layer 3 is connected to an external electric circuit, The component A is electrically connected to the 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 scope of the present invention. Although the multilayer wiring portion 4 formed by alternately laminating the organic resin insulating layers 2 and the thin film wiring conductor layers 3 is applied only on the upper surface, the multilayer wiring portion 4 may be provided only on the lower surface side of the substrate 1. , On both upper and lower main surfaces.

[0043]

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 a very high density. .

According to the multilayer wiring board of the present invention, since a hole is provided in the uppermost organic resin insulating layer and a bonding pad is formed on the bottom of the hole, the distance between adjacent bonding pads is substantially reduced. As a result, when connecting the electrodes of active components such as semiconductor elements, capacitors, and passive components such as resistors to the bonding pad via a brazing material made of solder or the like, a part of the brazing material is adjacent to the bonding pad. The electrodes such as the semiconductor elements can be accurately and electrically connected to the predetermined bonding pads without flowing to the pads, and the semiconductor elements and the like can always be normally operated.

Further, according to the multilayer wiring board of the present invention, at least a part of the lower end side of the inner wall of the hole formed in the uppermost organic resin insulating layer is buried in the bonding pad. And the uppermost organic resin insulating layer are bonded very firmly, and the thermal stress generated due to the difference in the thermal expansion coefficient between the organic resin insulating layer and the semiconductor element, capacitor element, etc. is repeatedly applied to the joint between them. The bonding pad does not peel off from the organic resin insulating layer even if it is done, which makes the connection reliability of the active components such as semiconductor devices and the passive components such as capacitors and resistors to the thin film wiring conductor layer extremely high. Can be made.

[Brief description of the drawings]

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

FIG. 2 is an enlarged sectional view of a main part of the multilayer wiring board shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Organic resin insulation layer 2a ... Top organic resin insulation layer 3 ... Thin film wiring conductor layer 4 ... Multilayer wiring part 7 ... Bonding pad 8 ... Through hole 9: Through-hole conductor 10: Hole provided in uppermost organic resin insulating layer A: Electronic component

Claims (1)

[Claims] An organic resin insulating layer and a thin-film wiring conductor layer are alternately laminated on a substrate, and a thin-film wiring conductor layer positioned above and below is formed on an inner wall of a through hole provided in the organic resin insulating layer. It is electrically connected via a hole conductor, and on the bottom of the hole provided in the uppermost organic resin insulating layer,
A multilayer wiring board comprising a bonding pad electrically connected to the thin-film wiring conductor layer and connected to an external electronic component, wherein at least a part of a lower end side of the inner wall of the hole is embedded in the bonding pad. A multilayer wiring board characterized by having been made.