JPH10209611A - Manufacture of high-density wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a high-density wiring board wherein migration between wiring electrodes can be prevented. SOLUTION: A pasty composition 2 of ITO(indium tin oxide) is printed on a fired ceramic substrate 1 in a specified pattern. A pasty composition 3 composed of at least organic binder and solvent containing Ag-Pt as conductor material, smaller in size than the specified pattern, is printed on a thick film of the formed pasty composition. The substrate with the thick-film pattern of the pasty composition formed thereon is fired. As a result, since upper electrodes 3 are not in direct contact with the ceramic substrate 1, an electrode film 2 positioned at lower level is capable of preventing migration between conductors due to the ionization of the upper electrodes 3. Therefore, defect in the substrate due to short-circuiting in the wiring electrode pattern can be prevented.

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 high-density wiring board for mounting semiconductor LSIs, chip components, etc. and interconnecting them.

[0002]

2. Description of the Related Art In recent years, semiconductor LSIs, chip components, and the like have been reduced in size and weight, and it has been desired to reduce the size and weight of wiring boards on which they are mounted. In order to meet such demands, forming high-density wiring on a ceramic wiring substrate or a resin substrate and making the wiring thinner is regarded as important in today's electronics industry.

[0003] The conductor composition as an electrode material used for this wiring board is generally a paste composition in which a conductive metal, an inorganic oxide, and a glass powder are dispersed in an organic medium. Currently, the conductor materials used are generally A
g, Cu, Pd or mixtures thereof are used. These metals have lower conductor resistance than conventionally used tungsten, molybdenum, and the like, and can be used with safe equipment at low cost.

As an invention using these conductor materials, Japanese Patent Application Laid-Open No. Hei 5-21934 discloses a method of obtaining an electrode by using a Pt-Ag-based or Ag-Pd-based paste for an electrode of a substrate for a hybrid integrated circuit. ing. Further, as an invention using a Cu electrode, there is JP-A-57-53321.
In this method, a wiring pattern is formed by screen printing a Cu paste on a substrate, and after drying, a temperature (8
The firing is performed in a nitrogen atmosphere with a controlled oxygen partial pressure so that Cu is not oxidized and organic components in the conductor paste are sufficiently burned without oxidizing Cu.

[0005]

As described above, Ag, Cu, Pd or a mixture thereof is used for a wiring board, but there is a problem here. That is the problem of migration in the wiring electrodes. Migration is a phenomenon in which metal ions move on the surface or inside of a material. Among them, in ion migration, two conductors are placed via an insulating material, and when a voltage is applied between the conductors, the insulation occurs. Leakage current flows along with hydrolysis of the material and generation of conductor ions, and the flow causes a phenomenon that conductor ions (mainly anodic ions) move between conductors.
If this phenomenon occurs between the wirings on the substrate, the electrode pattern is short-circuited, which causes a failure of the substrate. In order to reduce the size, if the density of the substrate becomes higher in the future, it is inevitable that the distance between the wirings will be narrower.
Therefore, an attempt to suppress migration is necessary.

The present invention has been made to solve the above problems.

[0007]

In order to solve the above-mentioned problems, the present invention provides a method in which Au or Ru is deposited on a fired substrate.
The paste composition of O ₂ or ITO is printed in a predetermined pattern, and Ag, Ag-Pd, or Ag-Pd is formed on the thick film of the formed paste composition.
Pt, or at least an organic binder containing a powder of Cu as a conductive material, a paste composition comprising a solvent,
The printing is performed in a size smaller than the predetermined pattern size, and the substrate on which the thick film pattern of the pace-like composition is formed is baked, whereby the migration can be suppressed, and the substrate due to the short-circuit of the wiring electrode pattern is formed. Can be prevented.

[0008]

The invention according to claim 1 of the embodiment of the present invention performs printing Au on a substrate subjected to calcination, or RuO _2, or a paste-like composition of the ITO in a predetermined pattern, the formation Ag, or Ag-Pd, or Ag-Pt, on the thick film of the paste composition thus obtained.
Alternatively, at least an organic binder containing a Cu powder as a conductive material, a paste-like composition comprising a solvent, and printed in a size smaller than the predetermined pattern size,
A method for manufacturing a high-density wiring board, characterized by baking a substrate on which a thick film pattern of a pace-like composition is formed, wherein Au or Ru is a material that is difficult to ionize.
Ag or Ag on O ₂ or ITO electrode
-Pd, or Ag-Pt, or Cu is positioned so that the electrode of the conductive material is not larger than the size of the electrode pattern at the bottom, so that the upper electrode is not directly in contact with the ceramic substrate. The located electrode film can suppress the movement between conductors due to the ionization of the upper electrode, and as a result, can prevent the failure of the substrate due to the short circuit of the wiring electrode pattern.

The invention according to claim 2 is to print a paste composition of Au, RuO ₂ , or ITO in a predetermined pattern on the fired substrate, and then fire the substrate. On the thick film of the predetermined pattern, A
g, or Ag-Pd, or Ag-Pt, or a paste-like composition comprising at least an organic binder and a solvent containing a powder of Cu as a conductive material, and printing with a size smaller than the predetermined pattern size. A method for manufacturing a ceramic wiring board, comprising baking a substrate on which a thick film pattern of a paste-like composition is formed, wherein Au or Ru is located below an electrode of a conductive material.
By firing the O ₂ or ITO electrode separately from the upper electrode, alloying with the upper electrode can be prevented, and the lower electrode film can suppress the movement of ions of the upper electrode between conductors. As a result, This has the function of preventing the failure of the substrate due to the short circuit of the wiring electrode pattern.

According to a third aspect of the present invention, Au, RuO ₂ , or IT is formed on a green sheet made of glass ceramic containing at least an organic binder and a solvent.
Printing the paste-like composition of O in a predetermined pattern,
Ag, Ag-Pd, or Ag-Pt, or Cu is formed on the thick film of the formed paste-like composition.
At least an organic binder containing a powder of as a conductive material,
A paste composition composed of a solvent is printed at a size smaller than the predetermined pattern size, and a paste composition of Au, RuO ₂ , or ITO is formed on a thick film of the conductor paste composition. Printing with a size larger than the conductor thick film pattern size, laminating a required number of green sheets on which a thick film pattern of the paste composition is formed, and firing the green sheet laminate. This is a method for manufacturing a high-density wiring board, such as Au, RuO ₂ , or ITO.
The structure of the electrode film sandwiching the conductor electrode can suppress the movement of ions of the conductor material, and the wiring is formed in the inner layer or the surface layer in the low temperature fired glass / ceramic multilayer substrate, which is considered to be more likely to cause migration. In such a case, it is possible to prevent the failure of the substrate due to the short circuit of the wiring electrode pattern.

According to a fourth aspect of the present invention, there is provided a method for performing printing
u, or RuO ₂ , or ITO paste-like composition contains Au, RuO ₂ , or ITO powder, at least an organic binder and a solvent, and after firing, Au, RuO ₂ , or ITO conductive film 4. The method for manufacturing a high-density wiring board according to claim 1, wherein the paste is made of an organic metal. Alternatively, the electrode film of RuO ₂ or ITO has an effect of suppressing the movement of ions of the upper electrode between conductors.

According to a fifth aspect of the present invention, a paste composition of Au, RuO ₂ , or ITO is printed in a predetermined pattern on a resin-based substrate, and the thickness of the formed paste composition is determined. Ag or Ag-
Pd, or Ag-Pt, or at least an organic binder containing a powder of Cu as a conductive material, a paste-like composition comprising a solvent is printed in a size smaller than the predetermined pattern size, and the paste-like composition is printed. A method for manufacturing a high-density wiring board, characterized in that a thick film pattern is cured to form a conductor wiring, wherein an electrode of a conductor material is provided below an electrode of Au, RuO ₂ , or ITO. By being formed so as not to be larger than the size, it has an effect of suppressing migration even in a resin substrate such as a glass epoxy substrate, and can prevent a failure of the substrate due to a short circuit of the wiring electrode pattern.

[0013] According to a sixth aspect of the present invention, there is provided an image forming apparatus, comprising:
The paste composition of u, RuO ₂ , or ITO contains Au, RuO ₂ , or ITO powder, and at least an organic binder and a solvent are added. An epoxy resin or a phenol resin is used for the organic binder. 6. A paste according to claim 5, wherein
The use of such a hardening type paste makes it possible to adopt a structure that suppresses migration even on a resin substrate that is not fired.

An embodiment of the present invention will be described below with reference to FIGS. (Embodiment 1) Hereinafter, Embodiment 1 of a method for manufacturing a high-density wiring board of the present invention will be described with reference to the drawings.

FIG. 1 shows the structure of a ceramic substrate.
(A) is a sectional view of the entire substrate, (b) is a plan view of the surface layer, (c)
FIG. 2 is a schematic diagram showing a state in which the electrodes are bridged in a water drop test on the ceramic substrate of the present embodiment. An ITO electrode 2 is formed on a ceramic substrate 1, an Ag-Pt electrode 3 is formed thereon, and each wiring is connected by a terminal electrode 4.

The manufacturing method will be described below. A pattern of the ITO electrode 2 was formed on the ceramic substrate by screen printing using an ITO paste, and the substrate on which the pattern was formed was baked at a peak temperature of 850 ° C. for 10 minutes to form the ITO electrode 2. . Next, after the ITO electrode 2 of the ceramic substrate was formed, A-Pt paste
The pattern of the g-Pt electrode 3 and the pattern of the terminal electrode 4 were formed by screen printing. At this time, the Ag-Pt electrode 3
Was formed as a pattern smaller than the ITO electrode 2. Then, the substrate on which the thick film pattern is formed is baked at a peak temperature of 850 ° C. for 10 minutes to form an Ag-Pt electrode 3 and a terminal electrode 4. At this time, a substrate in which an ITO electrode was not formed under the Ag-Pt electrode was also manufactured as a comparative substrate. A drop test of the water droplet 5 was performed on the glass / ceramic substrate formed by the above operation.

This test is a method in which one drop of pure water is used as a gap drop between electrodes to bridge the electrodes and then to apply a voltage to both terminal electrodes. The test load voltage was 20 V, and the measurement was continued until the current value exceeded 10 mA. In the case of the substrate on which the electrode was formed using only Ag, the current exceeded 10 mA after 40 seconds. In comparison, the case in which Au was formed under the Ag electrode exceeded 10 mA in 300 seconds, and the time during which the overcurrent flowed was longer than that of the Ag electrode alone by 7 times or more.

From the above results, it can be seen that arranging the ITO electrode below the Ag-Pt electrode has the effect of suppressing migration.

(Embodiment 2) Hereinafter, Embodiment 2 of the method for manufacturing a high-density wiring board of the present invention will be described with reference to the drawings.

FIG. 2 shows the structure of the ceramic substrate.
(A) is a sectional view of the entire wiring board, and (b) is a plan view of the surface layer of the board. RuO ₂ electrode 1 on the surface of ceramic substrate 11
2. An Ag-Pd electrode 13 and a terminal electrode 14 for connecting between the respective wiring electrodes are formed thereon.

The manufacturing method will be described below. On the ceramic substrate 11, using the RuO ₂ paste to form a pattern of RuO ₂ electrode 12 by screen printing, RuO ₂
After the pattern of the electrode 12 was formed, a pattern of the Ag-Pd electrode 13 and a pattern of the terminal electrode 14 were formed by screen printing using an Ag-Pd paste. At this time Ag
The pattern of the Pd electrode 13 was formed in a smaller pattern than the pattern of the RuO ₂ electrode 12. Then, the substrate on which the thick film pattern is formed is heated at a peak temperature of 900 ° C. 10
Sintering is performed by holding the Ag-Pd electrode 13 and the terminal electrode 1
4 is formed. At this time, a substrate having no RuO ₂ electrode under the Ag-Pd electrode was also prepared as a comparative substrate.

A constant temperature / humidity load test was performed on the ceramic substrate formed by the above operation. This test is a method in which a voltage is continuously applied to both terminal electrodes and left for a long time in a thermo-hygrostat. The condition of the thermo-hygrostat is 60 ° C, 95% R
H, a test was performed at a continuous load voltage of 5.0 V, and a comparison was made at the short-circuit occurrence time. If there is no lower electrode of RuO ₂ , a short circuit occurs at 200H. But Ru
When the O ₂ electrode was formed at the lower portion, no short circuit occurred even after 1000 H.

As described above, even in the constant temperature / humidity load test,
By forming the lower electrode of RuO ₂ , Ag-Pd
Migration can be suppressed, and electrode short-circuit can be prevented.

(Embodiment 3) Hereinafter, Embodiment 3 of a method for manufacturing a high-density wiring board according to the present invention will be described with reference to the drawings.

FIGS. 3A and 3B show the structure of the glass-ceramic multilayer substrate. FIG. 3A is a cross-sectional view of the entire laminate, and FIG. 3B is a plan view of the surface layer. (C) to (e) are plan views of each inner layer. Forming an Au lower electrode 22 on a glass / ceramic substrate 21;
An Ag electrode 23 is formed thereon, and an Au upper electrode 2 is formed thereon.
4 are formed. The electrode film is connected to the extraction electrode 25, and each is connected to the surface layer of the multilayer substrate by the via electrode 26 and connected to the surface electrode 27.

The manufacturing method will be described below. Au by screen printing on glass / ceramic green sheet
The pattern of the Au lower electrode 22 is formed using the organic metal paste of
With the paste, the pattern of the Ag electrode 23 and the lead electrode 2
The pattern No. 5 was formed by screen printing. At this time, the pattern of the Ag electrode 23 was formed in a smaller pattern than the pattern of the Au lower electrode 22. Next, the Ag electrode 23
The pattern of the Au upper electrode 24 was formed on the thick film pattern of the above by screen printing using an organic metal paste of Au. At this time, the pattern of the Au upper electrode 24 was formed in a pattern larger than the pattern of the Ag electrode 23.

Next, a via hole is made with a puncher on a glass-ceramic green sheet on which no pattern has been formed, and a via pad is filled with an Ag paste in order to form a via electrode 26. Then, a required number of the green sheets on which the wiring electrode patterns were formed and the green sheets on which the via patterns were formed were laminated, and in this state, thermocompression bonding was performed to form a laminate. The thermocompression bonding conditions were a temperature of 80 ° C. and a pressure of 200 kg / cm ² . The green sheet laminate was fired at a peak temperature of 900 ° C. for 10 minutes, and the glass / ceramic substrate 21, the Au lower electrode 22, and the Ag electrode 2 were fired.
3 is an Au upper electrode 24, a lead electrode 25, and a via electrode 2
6 was formed.

Next, in order to establish connection with the via electrode 26,
The pattern of the surface layer terminal electrode 27 is formed by screen printing, and baked at a peak temperature of 850 ° C. for 10 minutes.
A surface terminal electrode 27 is formed. At this time, a substrate having no Au electrode formed on the upper and lower portions of the Ag electrode was also prepared as a comparative substrate. At this time, since the inner layer electrode uses an organic metal paste for Au, even if the Ag electrode and the upper and lower electrodes of Au are combined, the thickness is 12 μm, and there is no problem in the flatness of the substrate.

A constant temperature and humidity load test was performed on the glass / ceramic multilayer substrate formed by the above operation. The condition of the thermo-hygrostat is 60 ° C., 95% RH, continuous load voltage 5.
The test was performed at 0 V, and the comparison was made at the time of occurrence of short circuit.
When there is no upper and lower electrode of Au, short-circuiting has occurred in all the wirings in the inner layer at 100H. But Au
When the electrodes were formed on the upper and lower portions, no short circuit occurred even after 1000H.

Even in the case of being located in the inner layer of the glass-ceramic substrate, by forming the upper and lower electrodes of Au, migration of Ag can be suppressed, and short-circuiting of the electrodes can be prevented.

(Embodiment 4) A method for manufacturing a high-density wiring board according to Embodiment 4 of the present invention will be described below with reference to the drawings.

FIGS. 4A and 4B show the structure of the glass / epoxy resin substrate. FIG. 4A is a sectional view of the entire substrate, and FIG. 4B is a plan view of the surface layer. Au electrode 32 on glass / epoxy resin substrate 31
Is formed thereon, and an Ag electrode 33 is formed thereon, and each wiring is connected with a terminal electrode 34.

The manufacturing method will be described below. A pattern of the Au electrode 32 is formed on the glass / epoxy resin substrate 31 by using an Au epoxy-based curing type paste, and then the pattern of the Au electrode 32 is formed, and then the Ag epoxy-based curing type is formed. The pattern of the Ag electrode 33 and the pattern of the terminal electrode 34 were formed using the paste. At this time, the pattern of the Ag electrode 33 was formed in a pattern smaller than that of the Au electrode 32. Then, the substrate on which the thick film pattern is formed is maintained at 150 ° C. to cure the electrode film, thereby forming the Au electrode 32, the Ag electrode 33, and the terminal electrode. At this time, a substrate having no Au electrode formed under the Ag electrode was also prepared as a comparative substrate.

The glass / epoxy resin substrate formed by the above operation was subjected to a constant temperature and humidity load test. The conditions of the thermo-hygrostat are 60 ° C., 95% RH, and continuous load voltage of 2.0.
The test was conducted at V, and the comparison was made at the short-circuit occurrence time. A
If there is no u lower electrode, a short circuit occurs at 50H. However, when the Au electrode was formed at the lower portion, no short circuit occurred even after 1000 H.

Even in the case of a glass-epoxy resin substrate having large moisture absorption, by forming the lower electrode of Au, the migration of Ag can be suppressed, and the short circuit of the electrode can be prevented.

In the above description, four examples of the embodiment are described.
The present invention can be similarly applied to a wiring substrate such as a T or aramid resin substrate which requires electrode wiring. Further, the present invention includes Au, R
This is carried out with uO ₂ and ITO, but this is the same for conductive carbon, Pb ₂ Ru ₂ O ₇ , Bi ₂ Ru ₂ O ₇ , SO _2, etc., if the material is conductive and hard to ionize. An effect can be obtained. In the present embodiment, Au
Although the materials coming on the electrodes have been described as Ag, Ag-Pd, and Ag-Pt, similar effects can be obtained in the case of Cu.

[0037]

As described above, according to the present invention, the migration of the wiring electrode can be suppressed, and the failure of the substrate due to the short circuit of the wiring electrode pattern can be prevented.

[Brief description of the drawings]

1A is a cross-sectional view showing the entire structure of a ceramic substrate in a method for manufacturing a high-density wiring board according to a first embodiment of the present invention; FIG. 1B is a plan view of the surface of the ceramic substrate; Schematic diagram showing a state where the electrodes are bridged in the water drop test

FIG. 2A is a cross-sectional view showing the entire structure of a ceramic substrate in a method for manufacturing a high-density wiring board according to a second embodiment of the present invention; FIG.

FIG. 3A is a cross-sectional view showing the entire structure of a glass-ceramic substrate in a method for manufacturing a high-density wiring board according to a third embodiment of the present invention; FIG. (D) Inner layer plan view of the glass / ceramic multilayer substrate (e) Inner layer plan view of the same glass / ceramic multilayer substrate

FIG. 4A is a cross-sectional view illustrating the entire structure of a resin substrate in a method of manufacturing a high-density wiring board according to a fourth embodiment of the present invention;

[Explanation of symbols]

Reference Signs List 1 ceramic substrate 2 ITO electrode 3 Ag-Pt electrode 4 terminal electrode 5 water drop 11 ceramic substrate 12 RuO ₂ electrode 13 Ag-Pd electrode 14 terminal electrode 21 glass-ceramic substrate 22 Au lower electrode 23 Ag electrode 24 Au upper electrode 25 lead electrode 26 Via electrode 27 Surface layer terminal electrode 31 Glass / epoxy resin substrate 32 Au electrode 33 Ag electrode 34 Terminal electrode

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Hashimoto 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (6)

[Claims] An Au or R on a fired substrate
uO ₂ or indium tin oxide (hereinafter referred to as IT
O) is printed in a predetermined pattern on a thick film of the formed paste composition.
Ag, or Ag-Pd, or Ag-Pt, or at least an organic binder containing a powder of Cu as a conductive material, a paste-like composition composed of a solvent, printed in a size smaller than the predetermined pattern size, A method for producing a high-density wiring substrate, comprising baking a substrate on which a thick film pattern of a pace-like composition is formed. 2. The method according to claim 1, wherein the baked substrate is Au or R
After printing a paste-like composition of uO ₂ or ITO in a predetermined pattern, the substrate is baked, and Ag or Ag-P is formed on the thick film of the predetermined pattern.
d, or Ag-Pt, or at least an organic binder containing a powder of Cu as a conductive material, a paste-like composition comprising a solvent is printed in a size smaller than the predetermined pattern size, and the paste-like composition is printed. A method for manufacturing a high-density wiring board, comprising firing a substrate on which a thick film pattern is formed. 3. A paste composition of Au, RuO ₂ , or ITO is printed in a predetermined pattern on a green sheet made of glass ceramic containing at least an organic binder and a solvent, and the paste composition formed is formed. A paste composition comprising at least an organic binder and a solvent containing a powder of Ag, or Ag-Pd, or Ag-Pt, or Cu as a conductive material, on a thick film of the material, smaller than the predetermined pattern size. Printing is performed in a size, and a paste composition of Au, RuO ₂ , or ITO is printed on a thick film of the conductor paste composition in a size larger than the conductor thick film pattern size. A required number of green sheets on which a thick film pattern of the composition is formed are laminated, and the green sheets are laminated. A method for manufacturing a high-density wiring board, comprising firing a laminate. 4. The paste composition of Au, RuO ₂ , or ITO for printing is Au or R
contains uO ₂ or ITO powder, at least an organic binder and a solvent are added, and after firing, Au or RuO
₂ or method of manufacturing a high-density wiring board according to any one of claims 1 to 3, characterized in that the organic metal paste for forming the conductive film of ITO,. 5. Au or RuO on a resin-based substrate.
₂ or the paste composition of ITO is printed in a predetermined pattern, and Ag, Ag-Pd, or Ag-P is formed on the thick film of the paste composition thus formed.
t, or at least an organic binder containing a powder of Cu as a conductive material, a paste composition comprising a solvent is printed in a size smaller than the predetermined pattern size, and a thick film pattern of the paste composition is cured. Let
A method for manufacturing a high-density wiring board, comprising forming a conductor wiring. 6. The paste composition of Au, RuO ₂ , or ITO for printing is Au or R
6. The high-density wiring according to claim 5, wherein the paste contains uO ₂ or ITO powder, and at least an organic binder and a solvent are added, and the organic binder is a paste using an epoxy resin or a phenol resin. Substrate manufacturing method.