JPS61156895A - Manufacture of wiring 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] (Industrial application field) The present invention relates to a method for manufacturing a conductor wiring board for an integrated circuit.

(Prior Art and its Problems) As methods for manufacturing conductor-wiring ceramic substrates for integrated circuits, two-layer thin film methods and thick film methods have been put to practical use. In all of these methods, conductors are formed using a mask or screen on which a circuit pattern has been formed in advance, so a process is required to make the mask or screen, which lengthens the process and takes time to manufacture the entire wiring board. It was taking time.

In recent years, with the development of IC%LSI, a large number of moramic wiring boards have been used, but with the diversification of needs, there has been a growing tendency for circuit boards to be produced in small quantities and in high quality. It is necessary to manufacture within a short lead time.

To meet this demand, methods are being considered to directly draw circuit patterns on thick films using combinations, computers, microcomputers, etc., but they do not provide sufficient accuracy or
There were problems such as the time it took.

Furthermore, when circuits were formed using this method, the width and pitch of the conductors became large, making it difficult to increase the density of the circuits.Furthermore, with the development of ICs and LSIs, circuits became smaller, denser, and more powerful. , IC, and LSI have also become an important problem due to temperature rise due to heat generation. Conventionally, alumina substrates of different purity have been used as ceramic circuit boards, but this dual thermal conductivity and high power were prevented.

As a ceramic substrate with high thermal conductivity,
Silicon carbide has been used, but its range of use has been limited due to issues such as toxicity, processability, and cost.

(Objective of the Invention) The present invention solves all of the problems of these conventional techniques, and enables circuits to be manufactured in small quantities and in a wide variety of products by directly drawing conductors with high precision and high quality on a ceramic substrate with high thermal conductivity. The purpose of the present invention is to provide a method of manufacturing circuit boards in a short delivery time and at low cost.

(Structure of the Invention) The present invention is characterized in that by irradiating an aluminum nitride substrate with high-energy radiation, conductive wiring is formed on the irradiated portion of the substrate. A
) We succeeded in forming a conductor layer directly on the miniram.

That is, in many cases, aluminum nitride does not have a melting point under normal pressure or reduced pressure, and a decomposition reaction occurs.

Aluminum nitride (A, FN) has a temperature of 1900°C under normal pressure.
In this case, at the decomposition temperature, aluminum and nitrogen gas form together with metallic aluminum according to the following reaction formula.
If there is a low-temperature area nearby, the metal component will condense and become a liquid or solid that will be deposited on the substrate to form a conductive layer.

For example, if the above reaction occurs in the air, the metal may be oxidized by the oxygen in the air, but the nitrogen gas generated during decomposition is present near the reaction, so the oxidation reaction is not possible. It becomes possible to form a conductor layer by adhering to the AJN surface without causing any damage.

As described above, according to the method of the present invention, a high-energy mt-nitride ceramic surface is irradiated with a laser beam, an electron beam, etc., and a part of the surface is heated to a temperature higher than the decomposition temperature of the nitride ceramic, thereby causing a nitride decomposition reaction. Moreover, by taking advantage of the good thermal conductivity of aluminum nitride, decomposed metal aluminum gold is deposited on the high-energy beam irradiated area of the substrate where the decomposition reaction is occurring and the beam passes through to form a conductor layer. It is something. In addition, it has become possible to directly draw all conductors on the substrate on which metallic aluminum is formed, even in the vicinity of the directly irradiated area on the substrate, and it has become possible to draw high-density circuits with high precision.

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

(Example 1) An aluminum nitride ceramic substrate was irradiated with a carbon dioxide laser under the following conditions in air.

Irradiation mode Pulse mode Peak output 1 kW Pulse frequency a IKHz Beam diameter 50 μm As a result, the irradiated area was cut into a V-shape to form a V-shaped groove and a metal aluminum layer was formed on the surface. This layer is made of gold and aluminum (Example 2) An aluminum nitride ceramic substrate was irradiated with γAG laser light in air under the following conditions.

Wavelength 1: 60μm output 60W pulse frequency 1
7KH2 Scanning speed 30 mm/, 71 e c
ROHM Sumi 80 μm As a result, the irradiated area was cut into a V-shape, a ■-shaped groove was formed, and a layer of metallic aluminum was formed on the surface.

It was confirmed by X-ray diffraction analysis that the surface layer was metallic aluminum.

The width of this conductor layer was 58 .mu.m and the depth was 38 .mu.m, and the resistance of the conductor was 250.mu.m.

(Example 3) An aluminum nitride ceramic substrate was irradiated with an electron beam beam in the following manner.

Output 60W Scanning speed jrnm/Bin beam diameter
30 μm As a result, the irradiated area was cut into a V-shape, a ■-shaped groove was formed, and a metal aluminum layer was formed on the surface.

It was confirmed by xX-ray diffraction analysis that the surface was covered with metallic aluminum.

The width of this conductor layer was 50 μm, the depth was 30 μm, and the resistance of the conductor was 10 Ω/i.

(Example 4) An aluminum nitride ceramic substrate was irradiated with YA (i laser light) under the same conditions as in Example 2 in a nitrogen gas atmosphere.

As a result, the irradiated area was cut into a V-shape, a square-shaped groove was formed, and a layer of metallic aluminum was formed on the surface.

It was confirmed by Ql X-ray diffraction analysis that the surface layer was metallic aluminum.

This conductor layer had a width of 60 μm and a depth of 40 μm, and the resistance of the conductor was 8Ω/i.

(Effects of the Invention) The uninvented manufacturing method has made it possible to directly form a conductor layer on an aluminum nitride substrate with high thermal conductivity using high-energy beams.

This makes it possible to form a conductor layer directly on the board without preparing a mask or screen as in the past, and with computers, microcomputers, etc. has become possible to manufacture at low cost.

In the present invention, carbon dioxide racer, Y
Although the embodiments using an AG laser and an electron beam have been described, since the principle of the present invention is to record a decomposition reaction by applying flat energy to a part of the substrate, laser beams and high-energy laser beams other than those in the embodiments have been described. A similar effect can be achieved with lines.

Furthermore, the same effect can be obtained in a neutral or reducing atmosphere as well as in air, nitrogen, vacuum, etc.

Claims (1)

[Claims] 1. A method of manufacturing a wiring board, which comprises irradiating an aluminum nitride substrate with high-energy radiation and forming conductor wiring on the irradiated portion of the substrate.