JPH04317389A - Forming method for wiring pattern - Google Patents

Abstract

PURPOSE:To easily obtain a wiring pattern having high reliability by forming paste containing polyimide resin and conductive particles as main materials on a board, thermally curing it, then collapsing a polyimide film formed on the surface of the conductor particles in the polyimide to tighten the particles for continuity. CONSTITUTION:A board 3 is coated with paste for forming a wiring pattern containing gold particles 1 and polyimide 2 as main ingredients, and thermally cured. Then, a mechanical pressure is applied to the particle 1, the polyimide 2 on the board 3 by a pressure roller 4 to collapse a film of the polyimide 2 formed on the particles 1. Accordingly, the particles 1, 1 are press-bonded between them to obtain an excellent electrical connection. Thus, a wiring pattern having high reliability can easily be formed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a conductor wiring pattern, and more particularly to a method for forming a pattern on a thick film multilayer substrate.

0002

[Prior Art] Conventionally, this type of thick film pattern formation method has been carried out on an alumina ceramic or glass ceramic substrate.
A conductive paste made of metal powder, organic solvent, and organic solvent is applied and formed using a thick film printing method, and after a drying process, it is sintered to form a pattern. Furthermore, pattern formation on polyimide films is carried out by thin film methods such as plating, sputtering, and CVD. Each of these pattern forming methods has its own characteristics, and the thick film printing method is characterized by a simple manufacturing process and the ability to form fine patterns relatively easily.
Widely and commonly used. The plating method and thin film method are characterized by the ability to form fine patterns on organic films, and are used for high-density mounting boards such as computers.

[0003] Also, as a technology that has recently attracted attention, there is a material in which conductor particles are added to epoxy or polyimide resin, which has a lower temperature for forming conductors than conductor paste for thick film printing, and can be formed on polyimide resin. Due to this, it has recently been widely used in semiconductor die bonding. Regarding the addition of conductive metals to organic resins, thermal conductivity,
Due to the requirement for electrical conductivity, noble metals such as silver and gold are often used.

0004

SUMMARY OF THE INVENTION However, the following problems occur in the above-mentioned conventional technology. That is,
In the thick film printing method using conductive paste, it is generally necessary to sinter it at a temperature of about 600°C to 920°C after printing to make it conductive, which is difficult to do when forming patterns on polyimide multilayer boards or glass epoxy printed boards. It is necessary to carry out the treatment at a temperature of about 350°C or less. For this reason, it is difficult to form a pattern on an organic film.

[0005] Furthermore, plating and thin film methods require technologies such as photolithography and etching, which complicate the manufacturing process and require expensive manufacturing equipment, resulting in high production lead times and manufacturing costs. There is a problem with becoming.

[0006] Regarding organic resins with conductor particles added, when the base resin and conductor particles are dispersed, the base resin having low thermal conductivity and high insulation properties is dispersed to form a film around the conductor particles. The thermal conductivity of the pattern after heating and curing is poor, and the conductor resistance becomes high.

An object of the present invention is to provide a method for forming a wiring pattern that solves the above problems.

[0008]

[Means for Solving the Problems] In order to achieve the above object, in the method for forming a wiring pattern according to the present invention, a paste mainly composed of an organic resin and conductor particles is used as a paste for forming a wiring pattern, By applying the paste onto a substrate to form a wiring pattern, curing it by heating, and applying pressure, or ultrasonic energy together with pressure, or ultrasonic energy and thermal energy to the wiring pattern. , the organic resin film formed on the surface of the conductor particles in the organic resin is destroyed, and the conductor particles are closely bonded to each other to make them conductive to each other.

[0009] Furthermore, the organic resin has polyimide as a main component, and the conductor particles are made of gold particles.

0010

[Operation] After forming a paste mainly composed of polyimide resin and conductor particles on a substrate and curing it by heating, the polyimide film formed on the surface of the conductor particles in the polyimide is destroyed, thereby making the conductor particles denser and conductive. This is what I did.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained in detail with reference to the drawings.

1 to 3 are cross-sectional views for explaining embodiments of the present invention, in which FIG. 1 shows a pressure method using a roller, and FIG.
3 is a diagram showing a method using an ultrasonic vibrator and a pressure force, and FIG. 3 is a diagram showing a method using an ultrasonic transducer, a pressure force, and a heating device. Figure 4
FIG. 2 is a sectional view for explaining the principle of the present invention.

In FIG. 4, a paste for forming a wiring pattern is coated on a substrate 3, the organic resin being polyimide and the conductor particles being gold particles as main components. In this state, a film of polyimide 2 is formed on the surface of gold particle 1. Therefore, the electrical resistance shows high resistance. The applied paste is then heated in an oven for approx.
It is cured under conditions of 50 to 420° C. and 30 to 60 minutes (cured state not shown). The polyimide gold used this time is a mixture of 10 wt% of polyimide precursor and 90 wt% of gold particles, which is a volume ratio of about 68:32, but by imidization by heat curing, The final volume ratio of polyimide to gold is about 30:70. In this state, the connections between gold particles are incomplete. Therefore, it is in an electrically unstable state with respect to temperature changes.

Therefore, in the embodiment shown in FIG. 1, by applying mechanical pressure to the polyimide gold 1 and 2 on the substrate 3 using a pressure roller 4, the film of the polyimide 2 formed on the surface of the gold particles 1 is destroyed. do. Thereby, the gold particles 1 and 1 are crimped and a good electrical connection is obtained. gold particles 1,
Since the bonding force between gold particles depends on the pressing force, temperature, and frictional force between the gold particles, a method in which these energies are added is considered.

The embodiment shown in FIG. 2 is an embodiment in which ultrasonic vibration and pressing force are applied as energy, and polyimide 2
, ultrasonic energy is applied to the surface of the gold particles 1 by the ultrasonic vibrating element 5 via the capillary 6, and the capillary 6 pressurizes the surface. According to this example, the bond between the gold particles becomes dense, and a stable electrical connection can be obtained.

The embodiment shown in FIG. 3 is different from the embodiment shown in FIG. 2 in that the substrate 3 is heated from the back side by a heating device 7, thereby achieving even more effective bonding between gold particles. It is.

[0017]

[Effects of the Invention] As explained above, the present invention provides the following advantages:
By applying mechanical energy and thermal energy, electrically stable connections can be obtained between the conductor particles in the paste, resulting in the formation of highly reliable wiring patterns.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing Example 1 of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a sectional view showing a third embodiment of the present invention.

FIG. 4 is a sectional view illustrating the principle of the present invention.

[Explanation of symbols]

1 Gold particles 2 Polyimide 3 Board 4 Pressure roller 5 Ultrasonic transducer 6 Capillary 7 Heating device

Claims (2)

[Claims] [Claim 1] A paste mainly composed of an organic resin and conductor particles is used as a paste for forming a wiring pattern,
Applying the paste on the board to form a wiring pattern,
The organic resin formed on the surface of the conductor particles in the organic resin is cured by heating, and by applying pressure, or ultrasonic energy and heat energy together with the pressure, to the wiring pattern. A method for forming a wiring pattern characterized by destroying a resin film and closely bonding conductor particles to each other to make them conductive to each other. 2. The method of forming a wiring pattern according to claim 1, wherein the organic resin contains polyimide as a main component, and the conductor particles are made of gold particles.