JPH0216788A - Ceramic printed wiring board - Google Patents

Abstract

PURPOSE:To form a fine conductor pattern with a plating conductor at a high accuracy and to realize a high precision ceramic printed wiring board by making a nickel-base layer of a plating conductor which is in contact with a thick film resistor layer at a terminal section of the thick film resistor layer. CONSTITUTION:At least a thick film resistor layer and a conductor layer formed through wet plating method are arranged on a ceramic board such as an alumina board, an aluminum nitride board, a silicon carbide board, and a glass board. A nickel-base layer is a plating conductor which is in contact with a thick film resistor layer at a terminal section of the thick film resistor layer such as RuO2 system, pyrochlore-type ruthenium oxide metal system, and nitride baked-type LaB6-system. According to this constitution, a fine conductor pattern can be formed with a high accuracy with a plating conductor and high precision of a ceramic printed wiring board can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a ceramic printed wiring board having high precision and high characteristics.

(Prior art) Attempts have already been made to combine a thick film resistor and an electroless plated film conductor on a ceramic printed wiring board using a wet plating method. A known method is to print a glass paste containing palladium on the terminal portion of the resistor after forming the resistor, then bake it, and perform electroless plating with photosensitive polyimide as an insulating layer and a plating resist.

(Problem to be Solved by the Invention) If a method for producing a ceramic printed wiring board using a wet plating method is used as is for a substrate containing thick film resistors, the processing chemicals included in the wet plating process may damage the resistors. is attacked, and the electrical characteristics of the resistor are significantly deteriorated. In addition, if you try to create a resistor after forming the conductor circuit, for example, if the resistor is a thick film fired resistor,
Since a temperature of 0° C. or higher is required, if the previously formed wet-plated conductor is a copper conductor, the conductor's properties will be impaired. Further, when a glass layer containing Pd is interposed in the terminal portion of the resistor as in the above example, there is a drawback that the resistor is accompanied by an increase in current noise. For this reason, it is preferable to deposit a conductive metal directly on the terminal portion of the resistor, but it has been difficult to obtain one that satisfies the electrical properties. The present inventors have already proposed a wiring board in which the surface of the resistor terminal part is roughened, a copper layer is used as the bottom layer, and heat treatment is performed, but even in this case, the conductivity and temperature coefficient of resistance are It has been found that although the current noise characteristics are excellent, the current noise characteristics are not necessarily sufficient in some cases.

(Means for Solving the Problems) The present inventors solved the problems of the prior art and arrived at the present invention as a result of intensive studies to create a ceramic printed wiring board having high precision and high characteristics. That is, in a ceramic printed wiring board in which at least a thick film resistor layer and a conductor layer formed by a wet plating method are disposed on a ceramic substrate, the thick film resistor layer and the conductor layer are formed at terminal portions of the thick film resistor layer. This is a ceramic printed wiring board characterized in that the plated conductor in contact is mainly a nickel layer.

The ceramic v-cured substrate in the present invention refers to an alumina-based substrate,
These are ceramic substrates such as aluminum nitride substrates, silicon carbide substrates, and glass substrates. Although the ceramic substrate can be used as is, it is preferable to use a ceramic substrate whose surface has been mechanically and/or chemically roughened in order to increase the adhesion of the plated conductor.

The thick film resistor layer in the present invention is, for example, Run2 type,
Pyrochlore type metal ruthenate type, nitrogen firing type LaB
It is formed by printing a thick film sintered type resistor paste of B type and tin oxide type on a ceramic substrate and then firing it under appropriate conditions.

In the present invention, when forming a conductive layer over the terminal portion of a thick film resistor, a protective insulating layer is placed on the thick film resistor layer other than the terminal portion and wet plating is performed. The protective insulating layer used is thick film sintered insulator paste,
and resin compositions can be used. The nickel-based layer refers to a nickel-based conductor layer that can be chemically precipitated using, for example, nickel/boron or nickel/phosphorus. The wet-plated conductor layer may be the same as the nickel-based layer that directly contacts the terminal portion of the thick-film resistor layer, but depending on the purpose, copper, silver, platinum, platinum group metals, etc. may be formed on the nickel-based layer.
It may be formed into a multilayer by combining electroless plating and/or electroplating of gold, ruthenium, and cobalt.

The plating conductor pattern can be formed by any of the substrate method, semi-additive method, and full additive method.

Although the conductor layer may be formed on the resistor layer terminal portion of the present invention as it is, it is better to form the conductor layer after surface roughening. Surface roughening here refers to mechanical and/or chemical roughening of the resistor terminal area, which increases the adhesion between the plated conductor and the thick film resistor, and is also suitable for reliability tests such as thermal shock. Mechanical roughening is the process of physically roughening the terminal surface by spraying relatively hard fine powder, such as ceramic or glue powder, onto the resistor terminal. This surface roughness is R
It is preferable to roughen the surface so that it falls within the range of . The above-mentioned surface roughening methods, which are methods for forming pores on the surface of resistor terminals on the level of an electron microscope, exhibit good terminal adhesion even when used alone, but it is preferable to use chemical roughening after mechanical roughening. By doing this, higher terminal adhesion can be obtained.

(Example) [Comparative example] Containing 96% alumina, m 50.8 mm, width 50.8
340mm, 0.635M thick white ceramic substrate
The substrate surface was appropriately roughened by immersing it in molten soda kept at .degree. C. for 10 minutes. Next, thick film fired resistor paste #6829 (sheet resistance: IKΩ/hole) (Dupont Japan) was applied to the roughened ceramic substrate.
] was coated in a desired pattern by screen printing and baked in air at 850°C for 10 minutes (total 35 minutes) to form a resistor layer. #913 on this resistor layer
7. Apply a thick film sintered glass paste for resistor protection (manufactured by DuponL Japan) by screen printing to cover the resistor surface and wall, leaving the resistor terminals, and heat at 550'C for 2 minutes (total 20 minute 1
．． "l) Fired in air. The shape of the resistor layer after firing is as follows.
Width 1.0m, length 1. It is 5 mm and 10 μm thick.

The shape of the glass insulating layer after firing is 1° OM in width and 1.5 in length.
nu++, thickness 1107z, forms a cross shape with the resistor layer, and 250 μm width at both ends of the resistor layer is not covered with the glass insulating layer as the resistor terminal portion. Apply 500 esh α-alumina powder to the entire surface of this substrate at a pressure of 1 kg.
/ci for 0.5 seconds to mechanically roughen it, then immerse it in a 4M NaOH aqueous solution at 50°C for 30 minutes, and after ultrasonic cleaning in pure water, semi-additively clean it so that it overlaps the resistor terminal. A plated conductor circuit pattern was formed. Specifically, first, the front surface of the substrate was coated with electroless copper plating. Electroless copper plating is performed using PTH process 4 (S
1.0 by hipley Far East)
An electroless copper plating film of μm thickness was obtained. Furthermore, a negative Menki resist was formed into a circuit pattern using a photosensitive dry film, and electrolytic copper plating was deposited to a thickness of about 10 μm. After electrolytic copper plating, the resist was peeled off and the electroless copper plated part was heated at 0.1 MHz Ox 10.1 MH.
It was removed by zSO6 etching.

For electrical properties, sheet resistance, current noise, and temperature coefficient of resistance were measured. Initial electrical properties and thermal shock test (immersed in -55°C trichloride for 5 minutes → left at room temperature for 10 seconds → +125
Table 1 shows the electrical property values after 25 cycles (thermal shock test in which one cycle was immersion in silicone oil of 'C for 5 minutes and then left at room temperature for 10 seconds).

[Example-1] A resistor protected by a glass insulating layer was formed on a white ceramic substrate with a roughened surface by the same method as shown in the comparative example. After degreasing this substrate, it was subjected to ultrasonic cleaning in pure water, and the entire surface of the substrate was coated with electroless nickel plating. Electroless Nickel plating uses Cataposit in the catalytic process.
44 process, electroless nickel plating N1-posit
468 (Shipley Far Ea
st), about 1. A nickel film of OIIm was obtained.

Thereafter, a plated conductor circuit pattern was formed using the same method as shown in Comparative Example I. 2. The composition of Kel film is N i /
B=99.7510.25.

Table 1 shows the results of the initial electrical properties and the electrical properties after 25 cycles of the thermal shock test.

[Example-2] A resistor protected by a glass insulating layer was formed on a surface-roughened white ceramic substrate by the same method as shown in the comparative example, and after mechanical roughening, it was soaked in a 4MUaOH aqueous solution at 50"C. 30
Immersion was performed for 1 minute. After this substrate was ultrasonically cleaned in pure water, the entire surface of the substrate was coated with electroless nickel plating. Electroless nickel plating uses Cataposi in the catalytic process.
t44 process, electroless nickel plating N1-pos
it 468 (both (Shipley Far
East), about 1. A nickel film of Oltm was obtained. Thereafter, a copper-plated conductor circuit pattern was formed using the same method as shown in Comparative Example (2). The composition of the nickel film is N
i/B = 99.75/0°25.

Table 1 shows the results of the initial electrical properties and the electrical properties after 25 cycles of the thermal shock test.

[Example 3] A resistor protected by a glass insulating layer was formed on a surface-roughened white ceramic substrate by the same method as shown in the comparative example, and after mechanical roughening, it was soaked in a 4M NaOH aqueous solution at 50°C. 30
Immersion was performed for 1 minute. After this substrate was ultrasonically cleaned in pure water, the entire surface of the substrate was coated with electroless nickel plating. Electroless nickel plating uses Cataposi in the catalytic process.
t44 process, electroless nickel plating N1-pos
it 65 (both (Shipley Far
East), about 1. A nickel coating of Opm was obtained. Thereafter, a copper-plated conductor circuit pattern was formed using the same method as shown in Comparative Example I. The composition of the nickel film is Ni
/P = 90/10. Table 1 shows the results of initial electrical properties and electrical properties after 25 cycles of thermal shock testing.
It was shown to.

Table sheet resistance value Current noise (KΩ/mouth) (dB) Comparative example Initial value thermal shock test 1.1500 1.1560 Example (-1) Initial value thermal shock test 1.1500 Part 1.1510 -23 Resistance temperature Coefficient (ppm/K) 5°C → 125°C 5°C → -55°C = (Equity) (Effect of the invention) By carrying out the present invention, the conductor pattern can be plated without impairing the original characteristics of the thick film resistor. The ability to form conductors with fine precision and spacing is extremely useful for improving the precision and characteristics of ceramic printed wiring boards.

Patent applicant Toyobo Co., Ltd. Example (-2) Initial value thermal shock test 1.1500 -25 1.1505 -25 Example (-3) Initial value thermal shock test 1.1500 -25 1.1505 -25 Comparison The measured values of Examples and Examples are the average values of n=20 Procedural amendment (voluntary) September 28, 1985 1゜λ 3゜Indication of incident 1987 Patent application No. 187495 Name of invention Ceramic printed wiring board Relationship with the case of the person making the amendment Detailed description of the invention in the specification of the patent applicant No. 2-2-8 Dojimahama, Kita-ku, Osaka City Contents of the amendment (1) r on page 5, line 4 of the specification ~ is also possible. ” and “In the present invention” in the fifth line, “In the ceramic printed wiring board of the present invention, compared to a ceramic printed wiring board obtained using a thick film baking paste in which printing and baking are repeated, By shortening the process,
It has excellent advantages such as cost reduction and easy double-sided wiring using through holes. ” is inserted.

■ "Resin composition" on page 4, line 12 of the specification is corrected to "resin composition."

Showa Year Month Day (voluntary)

Claims (1)

[Claims] (1) In a ceramic printed wiring board in which at least a thick film resistor layer and a conductor layer formed by wet plating are arranged on a ceramic substrate, the thick film resistor layer is disposed at the terminal portion of the thick film resistor layer. A ceramic printed wiring board characterized in that the plated conductor in contact with the plated conductor is mainly composed of nickel.