JPH03145191A - Electrode of circuit board - Google Patents

Abstract

PURPOSE:To obtain an electrode of a circuit board which is connected tightly to a protrudent electrode and low in resistance at its connected part with the protrudent electrode by a method wherein the electrode is composed of a first material and a second material, the first material is conductive and lower than the second material in resistance, and the second material is higher than the first material in adhesion to the protrudent electrode. CONSTITUTION:An electrode is composed of a first part of highly conductive first material and a second part formed of second material excellent in adhesion. The first part is a low resistance part 20, the second part is composed of tight contact parts 30 formed on the low resistance part 20, and the low resistance part 20 electrically connects an electrode 10 with the protrudent electrode of an electronic part low in resistance and is formed of material lower than that of the tight contact part 30 in resistance. Mo is preferably employed as the first material of low resistance. On the other hand, the tight contact part 30 serves as a part which tightly connects the protrudent electrode of an electronic part with the electrode 10 and is formed of material higher than that of the low resistance part 10 in adhesion. It is preferable that ITO is used as the second material excellent in adhesion.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to electrodes for circuit boards, and in particular, to electrodes for circuit boards that are connected with good adhesion to protruding electrodes of electronic components, and that do not cause connection failures at the connection portions. The present invention relates to an electrode for a circuit board having a low resistance at a connecting part.

(Prior art) A circuit board in which wiring is formed on an insulating substrate,
Those on which electronic components such as C are mounted have electrodes on the circuit board for connecting the protruding electrodes of the electronic components and the wiring. Conventional circuit board electrodes are made of metal or ITO (ITO).
It is made of one type of conductive material such as ndium (TinOxide). The electrode and the protruding electrode of the electronic component are connected with a conductive adhesive.

(Problem H to be Solved by the Invention) However, the above-mentioned prior art has the following problems.

When the electrode is made of metal, the resistance is low at the connection between the electrode of the circuit board and the protruding electrode of the electronic component, but there is a problem of poor adhesion. Therefore, disconnection or poor connection may occur at the connection portion. Also, the electrode is
When made of O, the adhesion of the connection portion is good, but there is a problem of high resistance. The resistance value at this time is ten times or more greater than the resistance value when the electrode is made of metal. This increases the voltage drop at the connection, which causes I
C malfunctions are more likely to occur.

The present invention has been made to solve the above-mentioned problems, and its purpose is to connect with the protruding electrode of an electronic component with good adhesion, and to prevent a connection failure from occurring at the connection part.
An object of the present invention is to provide an electrode for a circuit board whose connection portion has low resistance.

(Means for Solving the Problems) The present invention provides #MII! protruding electrodes of electronic components via a conductive adhesive. an electrode for a circuit board, the electrode having a first portion made of a first material and a second portion made of a second material, the first material being electrically conductive; The resistance of the first material is lower than the resistance of the second material, and the adhesion of the second material to the protruding electrode is greater than the adhesion of the first material to the protruding electrode. is also high, thereby achieving the above objective.

Moreover, it is preferable that the first material is Mo.

Further, it is preferable that the second material is ITO.

(Example) The present invention will be described below with reference to an example. FIG. 1 is a perspective view showing the main parts of the example. At the end of the wiring 40 on the circuit board (not shown), an electrode 1O is provided for connecting the wiring 40 and a protruding electrode of an electronic component such as an IC.

Note that a plurality of electrodes having a structure similar to the electrode 10 shown in FIG. 1 are provided at predetermined positions of the wiring 40 having a predetermined pattern formed on the circuit board.

The electrode 10 has a first portion made of a first material with high conductivity and a second portion made of a second material with high adhesiveness. The first part is the low resistance part 20, and the second part is the contact part 30 formed on the low resistance part 20. The low resistance part 20 is a part for electrically connecting the protrusion II pole of the electronic component and the electrode 10 with low resistance, and the contact part 3
It is made of a material with lower resistance than the material of 0.

For example, a metal such as Mo1T5 is suitable as the first material with low resistance. On the other hand, the contact portion 30 is a portion for connecting the protruding electrode of the electronic component and the electrode 10 with good adhesion, and is formed of a material with better adhesion than the low resistance portion 20. For example, fTo is suitable as the second material with good adhesion. The shape of the contact portion 30 in this embodiment in plan view is striped, as shown in FIG.

Next, the manufacturing method of this example will be explained using FIG. 2. First, on a glass insulating substrate 1 that will become a circuit board,
Mo was deposited as the first material by sputtering to form a Mo film (300 OA in film thickness) 2 (see Fig. 2).
a)).

Next, an upper photoresist 3 is applied on the Mo film using a spin code, heated to a predetermined temperature to harden the photoresist 3, and then a predetermined area of the photoresist 3 is exposed and developed. was patterned into a predetermined shape (Fig. 2(b)). The pattern of this photoresist 3 includes wiring 40 made of Mo film 2 and low resistance part 2.
This determines the pattern of the circuit board, and is designed according to the purpose of the circuit board.

After heating and hardening the photo 1/cyst 3 again, the Mo film 2 is etched using the buttered photoresist 3 as a mask, thereby buttering the Mo film 2 and forming the low resistance part 20 of the wiring 4o and the electrode IQ. Figure 2 (C)). After this, the photoresist 3 was removed.

Next, ITO is deposited as a second material on the entire surface of the insulating substrate 1 by a sputtering method, and an ITO film (film thickness of about 20
00 large) 4 was formed (Fig. 2(d)).

A photoresist 5 is applied onto the 170M44 using a spin code, heated to a predetermined temperature to harden the photoresist 5, and then a predetermined area of the photo 1/cyst 5 is exposed and developed to form the photoresist 5 into a predetermined shape. It was patterned into a shape (Fig. 2(e)). The pattern of this photoresist 5 determines the pattern of the close contact part 30 made of the ITO film 4, and in this embodiment, the pattern of the low resistance part 20 is
Formed in stripes on top.

After heating and hardening the photoresist 5 again, using the patterned photoresist S as a mask, the ITO film 4 is
The ITo film 4 was patterned by etching to form the contact portion 30 of the electrode 10 (FIG. 2(f)).
). Thereafter, the photoresist 5 was removed, and the circuit board of this example was manufactured.

On the circuit board, each f! Equipped with electronic components. The protruding electrode of the electronic component and the electrode 10 are connected using a conductive adhesive.

The adhesion between the protruding electrode of the electronic component and the electrode 10 is improved by the striped adhesion portion 30. Further, during operation of the electronic component, current mainly flows through the low resistance portion 20 in the area where the contact portion 30 is not formed, so the connection resistance between the protruding electrode and the electrode 10 is low.

As described above, according to this embodiment, the electrode 10 of the circuit board and the protruding electrode of the electronic component are connected with good adhesion, and the resistance of the connection portion is low. Therefore, in addition to preventing disconnection or poor connection at the connection portion, the resistance of the connection portion is low, thereby preventing malfunction of the IC due to a voltage drop at the connection portion.

The shape of the close contact portion 30 is not limited to the striped shape of the above embodiment. If the surface of the electrode 10 to which the protruding electrode of the electronic component is bonded has a shape in which the low resistance portions 20 and the contact portions 30 are substantially alternately arranged, excellent adhesion and low connection resistance can be achieved. can be realized.

The concentric circle shape shown in FIG. 3 or the checkered pattern shape shown in FIG. 4 is suitable as the shape of the contact portion 30.

In addition, in any of the above embodiments, the low resistance part 2 made of Mo
As shown in FIG. It may be something. The shape of this low resistance part 20 is
Any shape may be used as long as the low resistance portions 20 and the contact portions 30 are substantially alternately arranged on the surface of the electrode 10 to which the protruding electrodes of the electronic component are bonded. The shape of the low resistance part 20 is the contact part 30 of the embodiment shown in FIG. 1, FIG. 3, or FIG.
A similar shape is suitable. In the embodiment shown in FIG.
The wiring 40 is formed integrally with the low resistance section 20 using the same material (Mo) as the low resistance section 20.

In the embodiment shown in FIG. 6, a low resistance part 20 made of Mo is formed on a close contact part 30 made of ITO. The wiring 40 is formed integrally with the contact portion 30 using ITO. Since the wiring 40 is made of ITO, it has a higher resistance than the wiring of other embodiments made of Mo.

The embodiment shown in FIG. 7 is made of the same material as the low resistance part 20 (Mo
) is formed simultaneously with the low resistance part 20 on the adhesive part 30 made of ITO. Distribution [40
may be formed separately from the low resistance part 20 using a different material from the low resistance part 20. Since the wiring 40 is bonded to the insulating substrate 1 via the adhesive part 30, the wiring 40
The adhesion between 0 and the insulating substrate 1 is high.

In addition, in any of the above examples, MoO20 and IT
Although the O4 film is formed by sputtering, it may be formed by other methods, such as electron beam evaporation.

Moreover, the electrode 10 may have one or more parts made of another material in addition to the first part made of the first material and the second part made of the second material. If the other material is highly conductive, this portion functions similarly to the low resistance portion 20. Further, if the other material has high adhesion, this portion functions similarly to the adhesion portion 30.

(Effects of the Invention) As described above, according to the present invention, the protruding electrodes of an electronic component such as an IC and the electrodes of a circuit board are connected with good adhesion, so that no connection failure occurs at the connection portion. Further, since the resistance of the connection portion is low, malfunction of [C due to voltage drop at the connection portion, etc.] is prevented.

4 No. 1 Fig. 1 is a perspective view showing an embodiment of the present invention, Fig. 2(a) -
(f) is a cross-sectional view for explaining the manufacturing method of the example, FIG. 3 is a plan view showing another example, FIG. 4 is a plan view showing still another example, and FIG. FIG. 6 is a sectional view showing still another embodiment, and FIG. 7 is a sectional view showing still another embodiment.

1... Insulating substrate, 2... Mo film, 3... Photoresist, 4... ITO film, 5"" photoresist, 1
0... Electrode, 20... Low resistance part, 30... Close contact part, 40... Wiring.

that's all

Claims (3)

[Claims] 1. An electrode of a circuit board to which a protruding electrode of an electronic component is connected via a conductive adhesive, the electrode comprising a first part made of a first material and a second part made of a second material. The first material has conductivity, the resistance of the first material is smaller than the resistance of the second material, and the second material has good adhesion to the protruding electrode. is an electrode of a circuit board, the adhesion of which is higher than that of the first material to the protruding electrode. 2. The circuit board electrode according to claim 1, wherein the first material is Mo. 3. The electrode for a circuit board according to claim 1 or 2, wherein the second material is ITO.