JPH08250859A - Ceramic multilayer wiring board and manufacture thereof - Google Patents

Abstract

PURPOSE: To obtain a ceramic multilayer wiring board which is excellent in positioning accuracy, insures a pattern structure, conductivity and joint strength for permitting fine wiring and holes ability to be plated and solder-wettability by providing an intermediate conductor layer comprising alloy of a specific composition comprising W and/or Mo on a lower layer of a surface conductor layer part of metal mainly containing Cu. CONSTITUTION: An intermediate conductor layer 2 comprising 40 to 90wt.% of W and/or Mo and 10 to 60wt.% of one or more kinds among Ir, Pt, Ti and Cr is provided on a lower layer of a uniform surface conductor layer part 1 mainly containing Cu. Thus, the board material is formed into a multilayer 4 with a wiring conductor forming material 3 mainly containing W and/or Mo, wherein paste for the intermediate conductor comprising 40 to 90wt.% of W and/or Mo and 10 to 60wt.% of one or more kinds among Ir, Pt, Ti and Cr is printed on the conductor 1 appearing on the surface layer, the board 4 and the internal conductor 3 are baked at the same time, and paste for forming a thick conductor film mainly containing Cu is printed and baked on the intermediate conductor layer 2 on the surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic multilayer wiring board used as an electronic circuit component and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a conventional conductor pattern forming method for a ceramic multilayer wiring board, a conductor forming method of post-attaching firing, in which a ceramic body containing a built-in conductor is fired in advance, and then a surface layer conductor pattern is formed and fired, Since it is not affected by shrinkage due to firing of the element body, it has been used as a method for ensuring the positional accuracy of the conductor. At this time, a metal containing molybdenum (hereinafter referred to as Mo) as a main component has been used as a post-installed conductor material. However, such a surface layer conductor has drawbacks that the conductor resistance becomes high when the conductor is thinned and the joint strength with the substrate becomes weak. Therefore, as a method of coping with the increase in conduction resistance when such a thin wire is used, a surface layer conductor formed by printing a conductor paste containing copper (hereinafter referred to as Cu) as a main component has been studied.
Further, as a method of preventing the bonding strength with the substrate from becoming weak, a method of adding a glass component to the surface layer conductor to form a pattern has been studied.

[Problems to be Solved by the Invention]

However, in the ceramic multilayer wiring board having the above-mentioned structure, when the Cu conductor is used to suppress the increase of the conduction resistance when the surface layer conductor is thinned, it is joined to the underlying ceramic multilayer board which is the element body. No strength can be obtained. In addition, in order to secure the bonding strength, if the amount of glass required to secure the bonding strength is added to the surface layer conductor, problems such as plating properties and solder wettability will occur, reducing the reliability during mounting. There was a problem of letting it.

The present invention has been made in view of the above-mentioned problems, and as a method of forming a post-installed conductor for a ceramic multilayer wiring board, it has excellent positional accuracy and can be thinned into a pattern structure and a forming method. Further, the present invention provides a ceramic multilayer wiring board that secures the conductivity and the bonding strength at that time and does not impair the plating property and the solder wettability.

[0005]

As a means for solving the above-mentioned problems, the structure of the present ceramic multilayer wiring board is the structure of a ceramic multilayer board containing a wiring conductor layer containing W or / and Mo as a main component. As a conductor wiring arranged on the surface, W or / and Mo of 40 to 90 wt% and Ir, P are provided under the surface conductor layer of a metal containing Cu as a main component.
10 to 60 wt% of 1 or 2 or more of t, Ti and Cr
% Intermediate conductor layer is provided.

Another structure of the ceramic multilayer wiring board according to the present invention is the structure of the ceramic multilayer wiring board in which the intermediate conductor layer further contains 30 wt% or less of the same material as the ceramic substrate.

The second aspect of the present invention is W or / and Mo.
Incorporating a wiring conductor forming material containing as a main component, a substrate material is formed in multiple layers, and W or / or
And Mo 40 to 90 wt% and Ir, Pt, Ti, Cr
1 or 2 or more kinds of 10 to 60 wt% is mixed with an organic binder to print an intermediate conductor layer paste,
A ceramic multilayer wiring board characterized in that a board and an internal conductor are simultaneously fired, and then a conductor thick film forming paste containing Cu as a main component is printed on the surface of the intermediate conductor layer and fired to obtain a conductor wiring. Is a manufacturing method.

Another method for manufacturing a ceramic multilayer wiring board according to the present invention is W or / and Mo 40 to 90 wt.
% And one of Ir, Pt, Ti, and Cr or one or more of 1
The wiring of the intermediate conductor layer paste in which 0 to 60 wt% is mixed with an organic binder and the conductor forming paste containing Cu as a main component is used for forming a wiring, and a ceramic multilayer substrate incorporating a wiring conductor layer containing W or / and Mo as a main component. After firing, a positive photosensitive resin is patterned by a photolithography method in a portion other than the portion where the pattern of the conductor appearing on the surface layer of the ceramic multilayer substrate is to be formed, and thereafter,
A first step of irradiating the positive photosensitive resin pattern with ultraviolet rays to form an opening of a resin pattern soluble in a developing solution, and a ceramic multilayer substrate having the opening formed of the positive photosensitive resin pattern. A second step of filling the intermediate conductor layer paste and drying the paste, a third step of removing the positive photosensitive resin filled with the paste with a predetermined alkaline developer, and the obtained intermediate conductor The fourth step of firing the pattern in which the layer paste is arranged, and then the wiring formation of the conductor forming paste containing Cu as the main component is performed in the first to fourth steps for forming the conductor containing Cu as the main component. A method of manufacturing a ceramic multilayer wiring board is characterized by including a fifth step of obtaining a conductor pattern containing Cu as a main component, except that the paste is used instead.

Another method of manufacturing a ceramic multilayer wiring board according to the present invention is W or / and Mo 40 to 90 wt.
% And one of Ir, Pt, Ti, and Cr or one or more of 1
The wiring of the intermediate conductor layer paste in which 0 to 60 wt% is mixed with an organic binder and the conductor forming paste containing Cu as a main component is used for forming a wiring, and a ceramic multilayer substrate incorporating a wiring conductor layer containing W or / and Mo as a main component. After firing, the negative photosensitive resin or film is patterned by a photolithography method to form an opening in the negative photosensitive resin or film in addition to the portion where the conductor pattern appearing on the surface layer of the ceramic multilayer substrate is to be formed. A first step of forming, a second step of filling and drying an intermediate conductor layer paste on the ceramic multilayer substrate on which the opening of the negative photosensitive resin or film is formed, and the negative filled with the paste Third step of removing the mold type photosensitive resin or film with a predetermined stripping solution, and the obtained pace for the intermediate conductor layer The fourth step of firing the pattern in which is arranged and then the wiring formation of the conductor forming paste containing Cu as the main component is replaced with the conductor forming paste containing Cu as the main component in the first to fourth steps. The method for producing a ceramic multilayer wiring board is characterized by including the same steps as those described above except that a fifth step of obtaining a conductor pattern containing Cu as a main component is performed.

Furthermore, another method for manufacturing a ceramic multilayer wiring board according to the present invention is W or / and Mo 40 to 90 wt.
% And one of Ir, Pt, Ti, and Cr or one or more of 1
This is a method for manufacturing a ceramic multilayer wiring board using an intermediate conductor layer paste prepared by adding 0% to 60% by weight of 30% by weight or less of a co-material powder of the same material as the ceramics substrate and mixing it with an organic binder.

[0011]

Function: Ir, Pt, T in the intermediate conductor layer of the present invention
i and Cr are metals that suppress the reducing power of W or / and Mo, and a typical combination example with W or / and Mo is W and Ir. This combination will be mainly described below.
That is, since Ir forms a solid solution with W and is alloyed by sintering, the content of W alone is reduced, the reducing power of W acting on the Cu paste during sintering of the surface layer conductor is suppressed, and the sintering reaction of the Cu conductor is suppressed. It is a stable, dense, high-strength and highly conductive conductor.
Further, Ir is dissolved in a small amount in Cu in the step of firing the Cu conductor to form a strong joint layer near the interface between the intermediate conductor layer of W and Ir and the Cu conductor, thereby improving the joint strength of the Cu conductor. Let Due to the function of the intermediate conductor layer, even if the Cu conductor wiring in the ceramic multilayer wiring board is thinned, the conductivity is ensured and the conductor joining strength is maintained. Further, since the glass content in the surface Cu conductor can be reduced, the reliability at the time of mounting due to defects such as plating properties and solder wettability does not deteriorate. Further, the reason for adding the co-material of the same material as the ceramic substrate to the intermediate conductor layer of W and Ir is to make firing shrinkages coincide with or close to each other when the intermediate conductor layer and the ceramic body are simultaneously fired. , And acts to suppress dimensional variation due to peeling, warpage, etc. of the intermediate conductor layer after simultaneous firing.

Since the manufacturing method of the present invention can be applied to a normal thick film printing process, it is possible to suppress an increase in cost. Further, particularly in the case of forming a fine wiring or a conductor that requires positional accuracy and dimensional accuracy, the fine wiring can be formed by using the manufacturing method according to claims 4 and 5 using the photolithography method. It works so as to obtain a conductor with excellent accuracy.

[0013]

EXAMPLES The present invention will be described in detail with respect to a mixture of W and Ir, which is a typical combination as an intermediate conductor layer.
FIG. 1 shows the surface layer C of the same size on the intermediate conductor layer W-Ir.
FIG. 2 is a structural diagram of a ceramic multilayer wiring board provided with the u conductor 1, and FIG. 2 is a structural diagram of a ceramic multilayer wiring board provided with a finer surface Cu conductor 1 on the intermediate conductor layer W-Ir.

Example A Ir powder having an equivalent particle size distribution was added to W powder having an average particle size of 3 to 4 μm, and alumina was further added if necessary,
Ethyl cellulose resin was mixed mainly with an organic binder dissolved in a solvent to prepare an intermediate conductor layer paste.
The paste was printed on the surface layer portion in which the built-in conductor of the alumina green sheet laminated product containing the W wiring conductor 3 was connected by a through hole, and the paste was co-fired at 1550 ° C. in a reducing atmosphere. Next, the surface of the obtained ceramic substrate is coated with a positive photosensitive resin on the entire surface thereof and dried. Next, the surface conductor portion is selectively irradiated (exposed) with ultraviolet rays, and then developed with a developing solution to dissolve and remove the exposed portion to obtain a positive photosensitive resin layer having openings in the surface conductor portion. Next, the entire surface of the positive photosensitive resin layer is irradiated with ultraviolet rays to form a resin layer soluble in the developing solution. Next, the opening of the positive photosensitive resin is filled with Cu paste and dried. Next, the positive photosensitive resin layer whose opening is filled with Cu paste is dissolved and removed with a predetermined alkaline developer. Next, the obtained Cu paste pattern was fired at 900 ° C. for 15 minutes to obtain a Cu conductor wiring on the intermediate conductor layer pattern. The obtained wiring pattern dimensions were the same for the intermediate conductor layer 2 and the surface Cu conductor 1. The joint strength of this sample was evaluated by the initial strength and the strength at 150 ° C. high temperature storage. The measurement method is as follows: After immersing the sample in a molten solder bath at 235 ° C ± 5 ° C, solder a lead wire for tensile test (wire diameter φ0.6mm) to a land of 2mm × 2mm square, and peel peeling method. Thus, the initial strength and the strength after storage at 150 ° C. for 1000 hours were measured.

Table 1 shows the composition of the sample and the evaluation of the bonding strength. In addition, as a comparative example, the test results of the examples other than the composition of the present invention are also shown in Table 1. In addition, No. of the comparative example. Nos. 6 and 7 have no intermediate conductor layer as the lower layer.

[0016]

[Table 1]

In the examples using the intermediate conductor layer paste of W and Ir shown in Example A and the intermediate conductor layer paste to which alumina powder was further added as a co-material, both the initial strength and the strength after the high temperature storage test were The results were large and good results were obtained in terms of plating property and solder wettability. Comparative example No. 1 in which the intermediate conductor layer is not provided as the lower layer. In 6 and 7,
In the composition in which the surface Cu conductor does not contain glass, the initial strength and the strength shortage after the high temperature storage test are remarkable, and the bondability with the alumina substrate is inferior to the examples. Further, in the composition in which a glass component was added to the surface Cu conductor in order to improve the bondability with the substrate, there were problems in the plating property and the solder wettability.

The W and Ir powders of the intermediate conductor layer have a W of 40
˜90 wt% and Ir of 10 to 60 wt%, and if the Ir content is less than 10 wt%, the amount of W alloyed is small and the residual amount of W alone is large and the control of reducing power becomes insufficient. . Further, if the content exceeds 60 wt%, the difference in the sintering characteristics between the Ir powder and the alumina substrate becomes large when co-firing with the substrate, and problems such as substrate warpage and peeling occur, which are unsuitable. More preferably, the Ir content is 35 to 50 wt%. If the amount of alumina powder added to reduce the difference in firing shrinkage between the ceramic green sheet and the intermediate conductor layer exceeds 30 wt%, the conductivity of the intermediate conductor layer is reduced, which is not preferable. The addition amount of alumina powder is more preferably 5 to 20 wt%.

In Example A, the intermediate conductor layer was formed by printing, and the surface Cu conductor was formed by Cu in the opening of the positive photosensitive resin.
Although the method of filling the paste has been described, it includes a configuration in which the manufacturing method can be modified depending on the pattern size and accuracy, such as when the pattern spacing of the surface layer conductor is narrow and thinning is required. For example, in the case of a surface conductor having a narrow pitch and fine wiring, which is difficult to achieve by the printing method, the built-in conductor and the green sheet laminated product are pre-fired simultaneously, and the intermediate conductor layer is WI to the opening of the positive photosensitive resin.
It is also possible to form a pattern by the filling method of the r (adding alumina powder if necessary) paste and fire it, and then pattern the surface Cu conductor by the filling method of the Cu paste into the opening of the positive photosensitive resin. Needless to say, it is possible to form the openings by using a negative photosensitive resin and film suitable for cost and in-line, instead of the positive photosensitive resin, and perform wiring formation in the same procedure. By this manufacturing method, the same effect can be obtained even in a surface conductor having a narrow pitch and fine wiring.

When the intermediate conductor layer and / or the surface Cu conductor is formed by the thick film printing method, the narrow pitch limit is 130 μm.
m (line width 80 μm), dimensional accuracy was ± 8 μm, and positional accuracy was ± 15 μm. When the paste is filled in the openings of the photosensitive resin by the photolithography method, the narrow pitch limit is 50 μm (line width 20 μm), the dimensional accuracy is ± 3 μm, and the positional accuracy is ± 6 μm.

Further, the width of the intermediate conductor layer and the width of the surface Cu conductor are determined within a range in which the insulation interval is secured and a mounting defect such as a solder bridge does not occur, and as shown in FIG. Even if the width of the lower intermediate conductor layer 2 is wider than that of the surface Cu conductor 1, the same effect can be obtained.

Further, it goes without saying that the Cu conductor obtained on the intermediate conductor layer may be subjected to a plating treatment such as Ni-Au which is usually carried out for the purpose of preventing oxidation or improving the jointability with solder. Absent.

-Example B- In the intermediate conductor layer of Example A, the same intermediate conductor layer and surface layer were used for an example in which a part of W was replaced by Mo and an example in which Pt, Ti, Cr were used instead of Ir. A Cu conductor layer was formed and the same strength test was performed. Table 2 shows the test results of the composition of the intermediate conductor layer and the bonding strength.

[0024]

[Table 2]

[0025]

As is apparent from the above description, according to the structure of the ceramic multilayer wiring board of the present invention, since the intermediate conductor layer is provided under the surface layer conductor, it becomes conductive as a conductor for post-baking. It has an effect that an excellent Cu conductor can be used and the bonding strength with the underlying ceramic multilayer substrate can be secured. Further, since the glass content in the surface Cu conductor can be reduced, there is an effect that it is possible to supply a ceramic multilayer wiring board which does not have defects due to plating properties and solder wettability and which does not impair reliability during mounting.

Further, according to the method for manufacturing a ceramic multilayer wiring board of the present invention, a paste filling method is used to fill the openings of the positive photosensitive resin using the photolithography method even when the surface layer conductors have a narrow pitch and fine wiring. Since it is used, there is an effect that higher density wiring is possible and the yield can be improved.

Furthermore, by adding powder of the same material as that of the ceramic substrate to the intermediate conductor layer of the present invention as necessary, the difference in firing shrinkage with the underlying ceramic green sheet can be alleviated, and dimensional variations, etc. It has the effect of stabilizing the quality.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

FIG. 2 is a schematic view showing another embodiment of the present invention.

[Explanation of symbols]

1 ... Surface Cu conductor, 2 ... Intermediate conductor layer, 3 ...
W wiring conductor, 4 ... Ceramic substrate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshikazu Nakata 4-53-3 Kitahama, Chuo-ku, Osaka-shi, Osaka Sumitomo Metal Industries, Ltd.

Claims (6)

[Claims] 1. As a conductor wiring arranged on the surface of a ceramic multilayer substrate containing a wiring conductor layer containing W or / and Mo as a main component, W is formed under a surface conductor layer portion of a metal containing Cu as a main component. Or / and Mo of 40 to 90 wt% and one or more of Ir, Pt, Ti and Cr of 10 or more.
A ceramic multilayer wiring board comprising an intermediate conductor layer of 60 wt%. 2. The ceramic multilayer wiring board according to claim 1, wherein the intermediate conductor layer further contains 30 wt% or less of the same material as the ceramics board. 3. A wiring material for forming a wiring conductor containing W or / and / or Mo as a main component is incorporated to form a substrate material in multiple layers,
W or / and Mo40 to the conductor appearing on the surface layer
90 wt% and 10 to 60 wt% of Ir, Pt, Ti, or Cr, which is mixed with an organic binder, is printed, and an intermediate conductor layer paste is printed, the substrate and the inner conductor are simultaneously fired, and then the surface layer A method for producing a ceramic multilayer wiring board, characterized in that a conductor thick film forming paste containing Cu as a main component is printed on an intermediate conductor layer and fired to obtain a conductor wiring. 4. W or / and Mo 40 to 90 wt%
And one or more of Ir, Pt, Ti, and Cr 10
The wiring formation of the intermediate conductor layer paste and the conductor forming paste containing Cu as a main component, which is mixed with an organic binder in an amount of ˜60 wt%, is carried out by forming a ceramic multilayer substrate containing a wiring conductor layer containing W or / and Mo as a main component. After firing, a positive photosensitive resin is patterned by a photolithography method in a portion other than a portion where a conductor pattern appearing on the surface layer of the ceramic multilayer substrate is to be formed, and then the positive photosensitive resin pattern is irradiated with ultraviolet rays. First step of forming an opening of a resin pattern that is soluble in a developing solution, and filling and drying an intermediate conductor layer paste on the ceramic multilayer substrate in which the opening is formed by the positive photosensitive resin pattern. And a third step of removing the positive photosensitive resin filled with the paste with a predetermined alkaline developer, A fourth step of firing the obtained pattern in which the paste for the intermediate conductor layer is arranged is carried out, and then the wiring of the conductor forming paste containing Cu as a main component is formed in the first to fourth steps by the Cu paste.
A method for manufacturing a ceramic multilayer wiring board, comprising: a fifth step of obtaining a conductor pattern containing Cu as a main component, which is performed in the same manner except that a conductor forming paste containing as a main component is replaced. 5. W or / and Mo 40 to 90 wt%
And one or more of Ir, Pt, Ti, and Cr 10
The wiring formation of the intermediate conductor layer paste and the conductor forming paste containing Cu as a main component, which is mixed with an organic binder in an amount of ˜60 wt%, is carried out by forming a ceramic multilayer substrate containing a wiring conductor layer containing W or / and Mo as a main component. After firing, the negative photosensitive resin or film is patterned by photolithography to form an opening in the negative photosensitive resin or film in addition to the portion where the conductor pattern appearing on the surface layer of the ceramic multilayer substrate is to be formed. A second step of filling and drying an intermediate conductor layer paste on a ceramic multilayer substrate in which the opening of the negative photosensitive resin or film is formed, and a negative type filled with the paste Third step of removing the photosensitive resin or film with a predetermined stripping solution, and the obtained intermediate conductor layer pace A fourth step of firing a pattern in which the conductors are arranged, and then wiring formation of a conductor forming paste containing Cu as a main component in the first to fourth steps.
A method for manufacturing a ceramic multilayer wiring board, comprising: a fifth step of obtaining a conductor pattern containing Cu as a main component, which is performed in the same manner except that a conductor forming paste containing as a main component is replaced. 6. W or / and Mo 40 to 90 wt%
And one or more of Ir, Pt, Ti, and Cr 10
6. The method for producing a ceramic multilayer wiring board according to claim 3, 4 or 5, wherein a paste obtained by further adding 30 wt% or less of a co-material powder of the same material as that of the ceramic substrate to -60 wt% and mixing it with an organic binder is used.