JPS58225657A - Multilayer hybrid integrated circuit - Google Patents

Abstract

PURPOSE:To obtain the multilayer hybrid IC by a method wherein resistors are formed in a multilayer type on a substrate making a laser resisting protective resin layer as the interlayer insulating film, and laser trimming is performed. CONSTITUTION:Copper foils 2 of the desired pattern are provided on the substrate 1, and a resist mask is printed to form the Ni plating resistors 3. Then BN, Al2O3, etc., are mixed to epoxy resin 4 and is controlled to have permeability of 50% or less to laser, and the part other than connecting holes 5 with copper foils 2 and the fixing part of a circuit element 8 is silk screened. Then electrically conducting paths 6 according to electroless Ni plating, for example, are provided to be connected to foils 2, carbon resistive paint is printed and baked to provide the resistors 7, and laser trimming is performed to regulate to have the desired resistance value. At this time, although the laser beam cut off the resistors 7, it is scattered by the resin layers 4, and insulation between the resistors 3 of the lower layer and copper foils 2 is held favorably. According to this construction, formation of the hybrid IC in a small type can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multilayer hybrid integrated circuit, and particularly to a hybrid integrated circuit in which resistors are multilayered and can be laser trimmed.

In conventional hybrid integrated circuits, there have been many attempts to increase the number of layers of conductive paths. However, multilayering of resistors has not yet been realized. When multilayered, it reacts with the resin insulating film for multilayering, becomes compatible, and loses its paste composition, making it impossible to control the resistance value.

Furthermore, it is difficult to trim a multilayered resistor, and it is difficult to control the resistance value.

The present invention has been made in view of these drawbacks, and is intended to realize a multilayer hybrid integrated circuit that realizes multilayering of resistors. Embodiments of the present invention will be described in detail below with reference to the drawings.

As shown in the drawings, the multilayer hybrid integrated circuit according to the present invention includes a hybrid integrated circuit board (1), a first conductive path (2) made of voice foil provided on the board (1), and a first conductive path (2) made of a voice foil. A nickel-plated resistor (3) formed between the conductive paths (2) by electroless nickel plating, and a laser-resistant protective resin layer (4) covering the first conductive path (2) and the Chinese chive-like resistor (3).
), a second conductive path (6) provided on the resin layer (4) and connected to the first conductive path (2) via the hole (5), and a second conductive path (6). It is composed of a second carbon resistor (7) provided in between.

In such a structure, the hybrid integrated circuit board (1) is made of ceramic or an aluminum substrate whose surface has been treated with alumite.

The first conductive path (2) is formed on the entire surface of the substrate (1) by selectively etching a copper foil into a desired pattern.

The first nickel-plated resistor (3) is formed by screen printing a resist on the surface of the substrate (1) and electroless nickel plating on the exposed portion.

The laser-resistant protective resin layer (4) is the most characteristic feature of the present invention, and is an electrically insulating material in which an inorganic filler that does not transmit laser light is dispersed in a thermosetting or thermoplastic organic synthetic resin. be.

Epoxy resin was used as the thermosetting resin, and boron nitride (BN) and alumina (A120.
), Merck (3MgO.4SiO2.2H,O), etc. are used singly or in combination. Since the inorganic filler scatters the transmitted laser light and lowers the energy density, a protective effect can be obtained if the transmittance is 50% or less.

The laser-resistant protective resin layer (4) is applied by screen printing and completely covers the first nickel-plated resistor (3) and the first conductive path (2), at least in the area where multilayering is to be performed. Coating 1-ru. Note that screen printing is selectively performed except for the hole (5) for connection with the first conductive ji25 (2) and the portion to which a circuit element (8) such as a transistor is fixed.

The second conductive path (6) is formed in a desired pattern on the surface of the laser-resistant protective resin layer (4). The second conductive path (6) is formed by electroless nickel plating, or
Alternatively, it can be formed by screen printing with a paste. Note that this second conductive path (6) is also formed on the hole (5) at the same time to connect with the first conductive path (2).

The second resistor (7) is laser resistant to II! Resin layer (4)
formed between the upper second conductive path (6). The second resistor (7) is formed by screen printing and baking carbon resistance paint. The second resistor (7) is trimmed with laser light and adjusted to a desired resistance value.

Book 11. Off, 1 step, -Cv-f-light, 1 car 7.・Although the first resistor (7) is cut, its energy density is scattered by the laser-resistant protective resin layer (4), and the first nickel resistor (3) and the first conductive path (2
) can maintain good insulation.

As described in detail in Section F above, according to the present invention, it is possible to easily realize a multi-layered resistor, and to perform laser trimming of the upper layer of the resistor, which was previously considered impossible. As a result, the degree of freedom in circuit design of the hybrid integrated circuit is increased17, which is beneficial as it can contribute to miniaturization.

[Brief explanation of drawings]

The drawing is a cross-sectional view illustrating a multilayer hybrid integrated circuit according to the present invention. Explanation of main drawing numbers. (1) is a hybrid integrated circuit board, (2) is a first conductive path, (
3) is the first nickel-plated resistor, (4) is the laser-resistant protective resin layer, and (7) is the second resistor.

Claims (1)

[Claims] 1. A first conductive path on a hybrid integrated circuit board, a first nickel-plated resistor provided between the first conductive path, and a laser-resistant coating covering the first conductive path and the nickel-plated resistor. a protective resin layer; a second conductive path provided on the resin layer and connected to the first conductive path through a hole;
and a laser-trimmed second carbon resistor provided between the conductive paths of the multilayer hybrid integrated circuit.