JPS5867096A - Method of wiring to ceramic board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for wiring on the surface of a chemical laminated substrate.

Conventional technology for wiring ceramic substrates, thin film method,
There are thick film methods, direct bonding methods, etc.

In the thin film method, metal is vapor-deposited on a lamic substrate and then wired by etching. This method had the following drawbacks.

(1) Poor mass production; (Kan) The bonding strength between the ceramic and the vapor-deposited metal is low.

Therefore, from both cost and performance considerations, the application has been limited to millimeter-sized semiconductor substrates, and has not been applied to senna-sized ceramic substrates.

The thick film method is a method of wiring a ceramic substrate by printing and firing a paste made of noble metal particles. This method had the following drawbacks.

(1) Since the wiring is printed using the printing method, the conductor width is 15
(V) - The conductor is made of precious metals such as silver and palladium. Therefore, the cost is high.

In the direct bonding method, as shown in Japanese Patent Application Laid-Open No. 52-37914, metal steel with a copper oxide surface is placed on a ceramic substrate, and the ceramic is bonded by heating in an inert gas containing oxygen. Although it has the advantage of providing high bonding strength when bonding metal copper with metal, it has the following drawbacks.

(vl) As shown in FIG. 1, K on ceramic 11.

The trap that uses the metallic copper of the hatch part 12 as a conductive baton is
It was necessary to place metal steel punched in the shape of a conductor pattern on ceramic board, making it impossible to achieve finer details. moreover,
It was not possible to form butter 2 in an independent state surrounded by patterns; &lO The entire surface of the metal steel placed on the ceramic was not bonded to the laminated ceramic, and a non-bonded area was created, resulting in one bulge of metal copper. ”, resulting in a low yield.

A common drawback of the prior art is that it is not possible to equally form three-dimensional wiring on the plane and side surfaces of the ceramic substrate.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, achieve good quantity, high yield, high bonding strength, good electrical conductivity, form fine conductive patterns, and simultaneously wire the flat and side surfaces of a ceramic substrate. An object of the present invention is to provide a method for wiring a ceramic substrate to a ceramic substrate, which allows wiring to be performed on a ceramic substrate.

The wiring method for a ceramic substrate of the present invention includes a first wire made of a noble metal that forms a solid solution with copper on the surface of a ceramic substrate.
providing a layer, and further providing a second layer made of chemical copper oxide plating containing cuprous oxide and cupric oxide as main components;
Selectively remove areas that are not needed with resist; selectively plate areas that are needed; remove resist; areas that were under the resist are removed, but plating that is not covered by resist is removed; The removed portions are etched to the extent that they are not removed to form a ceramic wiring board, and the ceramic wiring board is then heated in an inert gas containing oxygen to form the second layer into metal steel. In the above, it is preferable that the first layer is made of metallic palladium formed by immersing it in a treatment solution containing divalent palladium and hydrochloric acid as essential components, and the second layer , the 2-side end ion, tartaric acid or an alkali metal salt of tartaric acid as a complexing agent for the 2-side end ion, formaldehyde as a reducing agent for the 2-side end ion, and a complex forming a regular tetrahedral complex with the 1-side end ion. It is preferable that the chemically oxidized copper plating is formed by immersing the steel in a chemically oxidized steel plating solution containing the chemically oxidized steel plating solution as an essential component. According to the wiring method for ceramic substrates of the present invention, it is possible to achieve high mass production, high yield, high bonding strength, good electrical conductivity, and formation of fine patterns. It is possible to wire the sides and sides at the same time.

The present invention will be described in more detail below with reference to the illustrated vertical cross-sectional view at 74-, - in FIG.

It is.

On the surface of the ceramic substrate 1 shown in each figure, as shown in circles,
A first layer 2 of precious gold maple is provided which is entirely in solid solution with copper.

Thereon, as shown in b, a second layer 3 of chemical oxidized steel plating containing 11IIs oxide and cupric oxide as main components is provided as a base.

As shown in d, the parts of the substrate that are not to be used as conductive patterns are selectively covered with 9 dinuto 4. Here, resist 4
As a method for selectively covering the substrate, for example, a printable base made by adding a filler, a solvent, etc. to a phenolic resin or p-zine-modified maleic acid resin can be used, which is printed in a non-conductive pattern and cured. Alternatively, a photoresist that is hardened or unhardened by exposure to light may be used. The method to be used depends on how dense a conductor pattern is required. The former is inexpensive but has a conductor pattern of 150 capes or more, while the latter is expensive but can form a conductor pattern of 150I1m or less. In other words, the essential properties of the resist material are as long as it can withstand the metallization process described below.

next,! As shown in FIG. 2, electroplating 5 is performed by applying electricity to the conductive pattern that is not covered with resist, thereby making only the conductive pattern thicker and making the conductive pattern a better electrical conductor. Generally, this plating 5 is preferably electrical steel plating. However, solder, nickel, gold, silver, etc. may also be used. If the characteristics required by users are to be satisfied, it is a matter of cost.

The thickness of the electroplating may satisfy the electrical conductivity required for a conductor. Those equipped with general semiconductors are only a few VA,
A thickness of 1000 m is sufficient.

If it is equipped with a 10,000VA class power element, electroplating of 1 (h-500gn) is sufficient.

Next, as shown in f, the resist 4 described above is peeled off. In this case, the method may be selected depending on the characteristics of the resist used. For example, a highly alkaline aqueous solution can be used for a printed resist, and an organic solvent such as isopropyl alcohol can be used for a photoresist.

Next, as shown in Figure 2, the non-conductor pattern portion is removed. The non-conductor pattern part under the resist 4 is not electroplated, that is, it is made of oxidized steel with a thickness of several millimeters, whereas the conductor pattern part is electroplated and is made of thicker metallic copper. It has become. There is no need to explain that if the entire surface of a ceramic copper substrate having such a structure is etched, the thin non-conductor pattern portion will be preferentially etched away.

It is sufficient that the etching liquid used has the property of dissolving the copper oxide that forms the non-conductive pattern, and it is sufficient to use hydrogen peroxide, cupric chloride, ferric chloride, chlorous acid, permanganate, and chromic acid. Any conventional etching solution can be used, such as etching solution.

Next, the substrate wired as described above is heated in an inert gas containing oxygen, and as shown in FIG. At the same time, the ceramic and the metal steel 3' are firmly bonded to form a ceramic copper substrate. When this ceramic-copper substrate is heated in an inert gas, the first layer of noble metal, which forms an all-solid solution with the copper, diffuses into the steel, and the ceramic and the second layer of copper oxide essentially come into contact. As a result, the copper oxide is heated and reduced to metallic steel, and the entire surface of the ceramic is firmly bonded to the metallic copper due to the covalent bond between the oxidized steel and the related ceramic.

The present invention will be explained in more detail below with reference to Examples.

Example 1 In this example, a ceramic substrate was coated with B of purity 96, 0. First, the following pretreatment of alkaline degreasing treatment and (b) neutralization treatment is carried out using Processed and wired.

It goes without saying that the following steps may include washing, drying, and other treatments as usual, if necessary.

(a) Alkaline degreasing treatment (pretreatment) Alkaline degreasing liquid composition: ``Sodium hydroxide''...100g water
,-・quantity condition near 0°C, where the whole is 1j,
Cleaning for s minutes (b) Middle treatment (pretreatment) Neutralizing liquid composition: 12N hydrochloric acid -150mj water
-・Quantity considering the whole as 1 No. Conditions: Room temperature, 1 minute cleaning e→ Plating nucleation treatment (gI layer formation) Plating nucleation liquid composition: Camelist 404, Silapray, USA Conditions: Room temperature, 5 minutes immersion) Chemical Plating treatment (second layer formation) Chemical plating solution composition: Cu804@5H, 0.50g Lodge; Ru salt -150g NaQ)l
・-Amount to make pH 1&0 57--Formalin--10 mjα, σ-dipyridyl
-・100mg water・-Amount to take 1J total Conditions: 40°C, 15h (5ttn) (e) Resist formation treatment Resist composition: Tokyo Ohkasha OM 85 Conditions: Substrate after completing the above steps) After degreasing and pickling, apply resist ink (3 μm) Exposure: 2 minutes Electroplating Electroplating solution composition: Pyrophosphate steel...90g Potassium pyrophosphate -550g Brightener
... i5mA polyphosphoric acid -, amount to make the pH 8.6 Water - amount to make the whole 1j Conditions: S Amp / dm", 'So minute (20,
can ) (g) Resist stripping treatment Resist stripping agent composition: Tokyo Ohkasha Nutripper-502 Conditions: 90°C, 2 minutes - Etching treatment Etching treatment liquid composition: Ferric chloride...40g 12N hydrochloric acid... 50mj water ・
...Quantity conditions = 50°C for 91 minutes (s) Heat treatment at 800°C in nitrogen containing 20 ppm oxygen, 150 minutes at 800°C, 1050°Cl2O minutes The above process makes the conductor pattern width 50 μm or more I was able to form a detailed oath turn. The pattern had sufficient bonding strength (5ookII/j) without any copper bulges, making it possible to form a fine pattern with high bonding strength that was impossible with conventional technology. →The plating nucleation solution in the process is a Pd-8n-Cj-based aqueous solution, in which metal palladium is dispersed as cotetraids, and when the ceramic substrate is immersed, li and q are formed on the surface of the ceramic substrate. This forms the first layer.

In this example, it was confirmed by X@ diffraction that the chemically plated precipitates in step (2) were mainly composed of cuprous oxide and cupric oxide.

Example 2 Example 1 except that the chemical plating treatment was performed as follows.
Exactly the same processing steps as in the case were followed.

2) Chemical plating treatment (second layer formation) Chemical plating liquid composition: CuSO4.5H@O-30g Rochelle salt...150g NaOH
' ・Amount with pH as 1 volume 37 formalin ・-jomIO-7 enanthroline ・! iomg conditions: 40°C, 1
, 5h (5 μm) in the process in this example), as in Example 1, the plating precipitates were determined by X-ray diffraction to be mainly composed of cuprous oxide and cupric oxide. It was a black film.

In this example, as in Example 1, the bonding strength was high and a fine pattern could be formed.

In addition, as a complexing agent to form a regular tetrahedral complex of Cu,
When nitrogen-containing heterocyclic compounds other than α, α'-dipyridyl and 0-phenanthroline described above, such as cuproine, neocubroine, and bucproine, were used, the same results as above were obtained.

Example 3 A wet lamic substrate (green sheet) on which a tungsten conductor was wired was used as a ceramic substrate.

By the same process as in Example 1, a fine conductor pattern of 100 Jln'l could be formed, and a fine pattern with high bonding strength of the circuit connected to the tungsten conductor on the ceramic surface could be formed.

! In fact, everything was the same as in Example 1 except that the plating nucleation treatment step (c) in Example 1 was changed to the following.

(c) Melting nucleation treatment (first layer formation) Melting nucleation liquid composition: AuC;
・-11g ethanol ...20 in total
Conditions for adjusting the amount to 0 m: After immersion at room temperature for 3 minutes, drying Even when the plating nucleation liquid having the above composition was used, the same results as in Example 1 were obtained.

Furthermore, as a result of the study, it was found that P, which forms a complete solid solution with copper,
d, Au, Pt, etc. were found to be effective for forming plating nuclei in the present invention.

Although the present invention has been described in detail above, the ceramic substrate to which it is applied may be any ceramic substrate containing AjtOl as a main component.

As described above, according to the present invention, three-dimensional wiring on the plane and side surfaces of a ceramic substrate, which was impossible with the conventional technology, can be easily mass-produced because the conductor does not bulge even once.
It has a high yield and can be formed into a fine conductor pattern with good electrical conductivity.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a conventional technique in which a copper foil is punched into the shape of a conductor to form a conductor. 2A to 2C are illustrative cross-sectional views sequentially showing the wiring process of the ceramic substrate of the present invention. 1.-Ceramic substrate 2..Precious metal 6..Chemical oxidized copper plating 3'..Metal steel 4..Resist
5...Electroplating first

Claims (1)

[Claims] (1) A first layer made of a noble metal forming a solid solution with copper is provided on the surface of the ceramic substrate, and an oxidized first layer is further provided on the surface of the ceramic substrate.
The first step is to provide a second layer of chemically oxidized steel plating containing copper and cupric oxide as a main component to form a base. The second step is to selectively cover unnecessary parts of the base with a resist; nucleus selection. A third step of selectively peeling off only the required portions of the substrate covered with a resist; a fourth step of removing the resist; the portions under the resist are removed; A fifth step of etching the plated portion without removing it to obtain a ceramic wiring board; heating the ceramic wiring board in an inert gas containing oxygen to form a second layer made of the chemically oxidized steel plating. 6th process with metal copper;
A method for wiring a ceramic substrate, comprising: (2) The first layer made of radium is formed by immersion in a treatment solution containing divalent baladium and hydrochloric acid as essential components.Claim 1 Wiring method to ceramic board described in section. (5) The second layer made of chemical copper oxide plating includes divalent copper ions, tartaric acid or an alkali metal salt of tartaric acid as a complexing agent for divalent copper ions, and formaldehyde as a reducing agent for divalent copper ions. The patent claim is a copper oxide plating formed by immersion in a chemical copper oxide plating solution containing as an essential component a complexing agent that forms a tetrahedral complex with monovalent copper ions. A method for wiring a ceramic substrate according to scope 1 or 2.