JPH05291744A - Manufacture of multilayer interconnection board and insulating board with multilayer metal layer - Google Patents

Abstract

PURPOSE:To obtain a multilayer interconnection board having high density and high interlayer connection reliability by pattern-etching only an upper layer metal to form an interlayer connecting metal pole, burying them in an insulating material, exposing a head of the pole by surface polishing, and forming an upper conductor pattern thereon. CONSTITUTION:A three-layer metal foil made of a first metal layer 11 of a copper layer, a second metal layer 12 of a nickel layer and a third metal layer 13 of a copper layer is batch etched to form a first interconnection pattern. Then, the metal 11 is etched to form an interlayer connecting metal pole 16. Epoxy resin varnish is coated-cured to a height of the pole 16 to form an insulating layer 17, and a head of the pole is present only at the interlayer connecting part by surface polishing. After a plated resist pattern 18 is formed, a second interconnection pattern 19 of an upper conductor pattern is formed by an electroless plating method. Thus, the interconnection part can be densified while reliability remains.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer wiring board and an insulating substrate with a multilayer metal layer.

[0002]

2. Description of the Related Art Interlayer connection technology is indispensable in the manufacture of multilayer wiring boards. The conventional interlayer connection technology is as follows: (1) After forming a hole through a wiring pattern and an insulating layer, metal is formed in the hole by plating or the like. (2)
After forming an insulating layer on a wiring pattern, a method of removing an insulating layer in a portion where interlayer connection is to be performed and then performing surface metallization and interlayer connection at the same time is performed.

[0003]

The method (1) is an interlayer connection method which is generally used in the production of multilayer wiring boards. However, since a drill is used to form the through holes, the diameter is less than 0.2 mm. It is difficult to form such a small diameter, and the hole position accuracy is ± 3.
0 μm or more is not enough. The method (2) is mainly used for semiconductor multilayer wiring formation. The diameter of the interlayer connection and the hole position accuracy are superior to the method (1) by one digit because the alignment technology using a photomask is used. ing. However, in the case of this method, since holes for interlayer connection remain, air bubbles remain in the holes when insulating layers are formed when wiring is further stacked and multilayered, and holes for interlayer connection are stacked on the holes for interlayer connection. There are many problems such as difficulty. The present invention provides a method of manufacturing a multilayer wiring board having high density and high reliability of interlayer connection, and an insulating substrate with a multilayer metal layer that can be used in the method.

[0004]

The first invention of the present application is
(1A) An insulating substrate with a multilayer metal layer in which a multilayer metal layer composed of at least two kinds of metal layers having different etching conditions is integrated with an insulating substrate is prepared. (1B) The multilayer metal layer is processed to A wiring pattern is formed, and (1C) the upper metal layer of the multi-layered metal layer forming the first wiring pattern is left except for a portion which will be a metal pillar for interlayer connection in a later step, and other portions. It is removed by utilizing the difference in etching conditions from the lower metal layer, and (1D) an insulating layer is formed on a portion other than the head of the metal column for interlayer connection, and (1E) is electrically connected to the metal column for interlayer connection. A method for manufacturing a multilayer wiring board, comprising the step of forming a second wiring pattern.

A second invention of the present application is (2A) preparing an insulating substrate with a multilayer metal layer in which a multilayer metal layer composed of at least two kinds of metal layers having different etching conditions is integrated with the insulating substrate, (2B). The upper metal layer of the multi-layer metal layer is removed by using the difference in etching condition between the metal layer of the lower layer and the other part, leaving the part to be the metal pillar for interlayer connection in a later step, ) The remaining metal layer is processed to form a first wiring pattern, (2D) an insulating layer is formed on a portion other than the head of the interlayer connection metal column, and (2E) conduction with the interlayer connection metal column. The method for producing a multilayer wiring board is characterized by including the step of forming the second wiring pattern described above.

An embodiment of the first invention of the present application will be described with reference to FIG. 50 μm thick copper first metal layer 11, 3 μm
The third metal layer side surface of the three-layer metal foil comprising the second metal layer 12 having a thick nickel layer and the third metal layer 13 having a copper layer having a thickness of 15 μm is K-treated (sodium hydroxide / sodium phosphate / After oxidation treatment with an aqueous solution of sodium chlorite), it was laminated and pressed with a glass cloth epoxy resin prepreg 14 which is an insulating substrate to prepare a laminate having a three-layer metal layer (FIG. 1A). As the insulating substrate, a synthetic resin film such as a polyimide film or an inorganic material such as a ceramic plate can be used. When a ceramic plate is used as the insulating substrate, the third metal layer 13 may be a thick film conductor or a plated conductor (in this case, a ceramic wiring board manufactured by Hitachi Chemical Co., Ltd., trade name "HMA
C "can be used. ) It is a general method to stack the three metal layers by plating.

Next, after forming a film resist having a thickness of 25 μm, the resist corresponding to portions other than the wiring pattern portion was removed by exposure and development. Subsequently, 68 μm of the three-layer metal foil was etched all at once by using a ferric chloride etching solution to form a first wiring pattern of the three-layer metal layer having a width of 0.2 mm (FIG. 1 (b)). However, the pattern of the interlayer connection portion was circular with a diameter of 0.6 mm. In order to process the three-layer metal foil to form the first wiring pattern, an electric discharge machining method, a laser machining method, a routing machining method, a combination machining method thereof or the like can be used in addition to the method using an etching solution.

Next, after forming a film resist again, after exposing and developing so that a resist pattern 15 having a diameter of 0.2 mm remains on the circular pattern (FIG. 1 (c)),
The first metal layer 11, which is a copper layer having a thickness of 50 μm, is etched with an ammonia-based etching solution that does not dissolve nickel but dissolves copper to form metal columns 16 for interlayer connection having a diameter of 0.2 mm and a height of 50 μm. (FIG. 1 (d)). At this stage,
The wiring pattern thickness was 18 μm. By the way, in this etching process, an alkali resistant solvent developing type resist was used. Considering interlayer insulation reliability, the height of the metal columns 16 for interlayer connection is preferably 20 μm or more.

The insulating layer 17 was formed by a method of applying and curing an epoxy resin varnish up to the height of the metal columns 16 for interlayer connection (FIG. 1 (f)). A thin epoxy resin layer was also formed on the metal columns for interlayer connection, but this could be removed by surface polishing, the surface was flat, and the state where the head of the metal column appeared only in the interlayer connection part was formed ( FIG. 1 (g)). The insulating layer may be formed by laminating or pressing a film material. Further, in order to improve the adhesion between the metal and the insulating layer, the insulating layer can be formed after the metal surface treatment or the interlayer adhesion promoting varnish is applied. There are various methods for exposing the head of the metal column for interlayer connection, but the polishing method is the easiest and is effective for planarizing the surface. At least a part of the head portion of the metal column for interlayer connection may be exposed.

After the plating catalyst is applied and the plating resist pattern 18 is formed (FIG. 1 (h)), the second wiring pattern 19 as the upper conductor pattern is formed by the electroless plating method.
Are formed (FIG. 1 (i)). On the other hand, when forming a wiring structure of three or more layers, a wiring pattern metal layer (third metal layer 13, second metal layer 13 or second metal layer 11) is formed on the insulating layer 17 and the interlayer connection metal pillar 11 in FIG. Panel plating of a metal layer 12) and a metal layer for interlayer connection (corresponding to the first metal layer 11) were performed, and then the first layer wiring patterns 12, 13 and the metal column 11 for interlayer connection were formed. The steps may be sequentially carried out according to the procedure.

In the multilayer wiring board thus obtained, the interlayer metal pillar head has a diameter of 0.2 mm, and thus the end surface distance of the connecting pillar head was 2.34 mm in the case of a 100 mil grid. Even if the upper conductor is designed with a margin of 0.2 mm / 0.2 mm (line / space), 5 pins between the pins, 0.1 mm / 0.1 mm
In the case of (line / space), it was possible to achieve high densification while maintaining the reliability of the wiring portion with 10 pins. The lower conductor was also designed with four pins between pins.

An embodiment of the second invention of the present application will be described with reference to FIG. First metal layer 21, 3μ of 50 μm thick copper layer
The third metal layer side surface of the three-layer metal foil consisting of the second metal layer 22 of m-thick nickel layer and the third metal layer 23 of the 15-μm-thick copper layer is K-treated (sodium hydroxide / sodium phosphate). / Oxidation treatment with an aqueous solution of sodium chlorite) and laminated press with a glass cloth epoxy resin prepreg 24 which is an insulating substrate to produce a laminated plate having a three-layer metal layer (FIG. 2A).

Next, the first metal layer 2 which is a copper layer having a thickness of 50 μm
After a film resist was formed on 1, the resist other than the portions corresponding to the metal columns for interlayer connection was removed by exposure and development. Here, an alkali resistant solvent developing type resist was used. An ammonia-based etching solution that does not dissolve nickel but dissolves copper is used to etch the first metal layer 21 of the upper copper layer having a thickness of 50 μm, and the diameter is 0.2 mm.
A metal pillar 25 for interlayer connection having a height of 50 μm was formed (FIG. 2).
(B)). At this stage, the thickness of the metal layer was 18 μm except for the portion of the metal column 25 for interlayer connection.

Next, an 18 μm metal layer was cut by an electric discharge machine of a numerical control drive system to form a first wiring pattern. The wiring pattern thus obtained is 0.1 mm /
It was 0.1 mm (line / space). At this stage,
A wiring pattern having metal columns for interlayer connection could be formed (FIG. 2C). Next, the insulating layer 26 was formed by a method of applying and curing an epoxy resin varnish up to the height of the metal columns for interlayer connection (FIG. 2D). A thin epoxy resin layer was also formed on the metal columns for interlayer connection, but this could be removed by surface polishing, the surface was flat, and the state where the head of the metal column appeared only in the interlayer connection part was formed ( FIG. 2 (e)).

After the plating catalyst is applied and the plating resist pattern 27 is formed (FIG. 2 (f)), the second wiring pattern 28 which is the upper conductor pattern is formed by the electroless plating method.
Are formed (FIG. 2 (g)). In this way, a high-density multilayer wiring board could be manufactured.

According to the first and second inventions described above, it is possible to manufacture a multi-layer wiring board having high density and high reliability of interlayer connection. It should be noted that this method is performed on both sides of the insulating base material, and if both sides are electrically connected by through holes, it is possible to further increase the number of layers. The multilayer wiring board of the present invention is also effective when used in combination with a multilayer wiring board formed by a usual method. At this time, the connection with the already formed wiring portion is, for example, through-hole connection.

In the present invention, a combination of metals of different materials, that is, a combination of different metals or an alloy of different metals is used as at least two kinds of metal layers having different etching conditions. It is practically preferable that the first metal layer and the third metal layer are made of the same material, and the second metal layer sandwiched therebetween is made of a different material.

In the present invention, the etching conditions are conditions for processing the wiring pattern by etching, and different etching conditions mean a method using an etching solution, an electric discharge machining method, a laser machining method, a routing machining method and these methods. This means that the conditions under which a wiring pattern can be processed by etching such as a combination processing method are different.

When the metal layer of the upper layer of the multi-layered metal layer is to be removed except for the portion which becomes the metal pillar for interlayer connection, a plurality of metal layers including not only the metal layer of the upper layer but also the metal layer of the upper layer. May be removed at the same time. That is, the metal column for interlayer connection may be composed of a plurality of metal layers. When the insulating layer is formed on a portion other than the head of the interlayer connecting metal column, at least a part of the head of the interlayer connecting metal column may be exposed.

[0020]

According to the present invention, it is possible to manufacture a multilayer wiring board having a high density and high reliability of interlayer connection. Further, by combining with a ceramic substrate, application to a multi-chip module substrate etc. has become easy.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the manufacturing process of the first invention.

FIG. 2 is a cross-sectional view showing the manufacturing process of the second invention.

[Explanation of symbols]

 11 First Metal Layer 12 Second Metal Layer 13 Third Metal Layer 14 Insulating Substrate 15 Resist Pattern 16 Metal Column for Interlayer Connection 17 Insulating Layer 18 Plating Resist Pattern 19 Second Wiring Pattern 21 First Metal Layer 22 Second metal layer 23 Third metal layer 24 Insulating substrate 25 Metal pillar for interlayer connection 26 Insulating layer 27 Plating resist pattern 28 Second wiring pattern

Claims (3)

[Claims] 1. (1A) An insulating substrate with a multilayer metal layer in which a multilayer metal layer composed of at least two kinds of metal layers having different etching conditions is integrated with an insulating substrate, and (1B) processing the multilayer metal layer. Then, the first wiring pattern is formed, and (1C) the metal layer of the upper layer of the multi-layered metal layer forming the first wiring pattern is left, leaving a portion to be a metal pillar for interlayer connection in a later step. Other parts are removed by utilizing the difference in etching conditions from the lower metal layer, and (1D) an insulating layer is formed on the part other than the head of the metal column for interlayer connection, and (1E) metal for interlayer connection. A method of manufacturing a multilayer wiring board, comprising the step of forming a second wiring pattern that is continuous with the pillar. 2. (2A) An insulating substrate with a multilayer metal layer in which a multilayer metal layer composed of at least two kinds of metal layers different in etching condition is integrated with an insulating substrate is prepared. The metal layer is removed by using the difference in etching conditions between the metal layer below and the metal layer for interlayer connection in the subsequent step, and the remaining metal layer is removed (2C). By processing, a first wiring pattern is formed, (2D) an insulating layer is formed on a portion other than the head of the interlayer connecting metal column, and (2E) a second wiring pattern electrically connected to the interlayer connecting metal column. A method of manufacturing a multilayer wiring board, comprising the steps of: 3. An insulating substrate with a multi-layer metal layer, wherein a multi-layer metal layer comprising at least two metal layers having different etching conditions is integrated with the insulating substrate.