JPS6343391A - Thick film circuit board - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a thick film circuit board composed of a printed circuit and surface-mounted chip components, and to reduce the mounting space for the chip components. This invention relates to a thick film circuit board that achieves higher mounting density.

(Conventional technology) In recent years, as electronic devices have become smaller and lighter, hybrid IG
has come into widespread use. This hybrid IC is generally constructed by soldering chip components that can be surface-mounted to a thick film substrate in which conductor and resistor layers are formed using film technology on an insulating substrate such as alumina.

By the way, there are two types of film technology printed wiring boards (hereinafter referred to as thick film circuit boards) used in this scale: one in which the wiring layer is formed before the resistor layer, and the other in which the wiring layer is formed after the resistor layer is formed. be. The former is applied to thick film circuit boards using silver-palladium based conductive paste, and the latter is applied to thick film circuit boards using copper based conductive paste.

FIG. 5 is a sectional view showing an example of the mounting configuration of chip components on the former thick film circuit board.

In FIG. 5, reference numeral 1 is an insulating substrate made of an insulator such as alumina, and one surface of this substrate 1 has
First, a wiring conductor layer 2.3.4 is formed by printing and firing a silver-palladium conductor base I. Wiring conductor layer 2
．． 3, a resistor layer 5 is formed by printing and firing a ruthenium oxide r-cum-based resistance paste in such a way that it straddles both. Also, the wiring conductor layer 3 near the wiring conductor layer 4 is formed on the resistor The portion not covered by layer 5 is extended to wiring conductor FfJ4rAq and constitutes deep component pad 3a. The chip component 6 has one electrode 6A connected to the pad 3a, and the other electrode 6B connected to the conductor layer 4 with solder 7.
is imposed via.

In the configuration shown in FIG. 5, the distance between the pad 3a and the wiring conductor layer 3 is determined by the size of the chip component 6, and conventionally, high density has been achieved by making the chip component 6 smaller. However, as the size of current chip components has reached its limit, miniaturization of these components is not enough.
It is not possible to arrange parts more densely. The size of the deep component 6 is generally larger than the length of the resistor layer 5 (for example, a large capacity capacitor), and when a large number of such components are used, the packaging density decreases and the board area is increased. There was a problem with the impact on

(Problems to be Solved by the Invention) With conventional chip component mounting technology, it is already difficult to increase the density by miniaturizing the chip components themselves, and the distance between wiring conductor layers is limited by the chip component size, making it difficult to increase the density of the chip components themselves. The problem was that the area was large.

The present invention has been made to solve the above problems,
The distance between wiring core layers for renaming chip components can be reduced,
The purpose is to provide a thick film circuit board that enables high-density packaging.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a chip component in which an electrode portion further overlaps an upper F/1 conductor portion for a resistance terminal formed on a formed flow resistor layer. It is characterized by being equipped with.

(Function) On an insulating substrate on which a resistor layer and a wiring conductor layer are formed using thick film technology, chip components are later attached as circuit elements. In the present invention, since the electrode part of the chip component is laminated and overlapped with the terminal part of the resistor layer, the mounting space of the chip component is shared with a part of the formation space of the resistor layer, and the chip component can be mounted accordingly. By narrowing the distance between the interconnection layers, high-density packaging can be achieved.

(Example) Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

FIG. 1 is a side sectional view showing an embodiment of a thick film circuit board according to the present invention.

In FIG. 1, the same parts as in FIG. 5 are denoted by the same reference numerals, and the fact that wiring conductor layers 2, 3.4 and resistor layer 5 are formed on an insulating substrate 1 is the same as in the prior art. This embodiment is different from FIG.
This is because a wiring conductor layer (also referred to as a wiring conductor layer) 8 is formed. In the chip component 6, one electrode 6A is fixed to the upper layer terminal portion 8 via solder 7, and the other electrode 4i6B is fixed to the wiring conductor layer 4 via solder 7.

According to the thick film circuit board configured as described above, the upper layer terminal portion 8 as a pad for soldering the chip component 6 is provided on the top of the resistor layer 5, so that the terminal of the resistor layer 5 is The use part 5a and the electrode 6A of the chip component 6 are aligned with each other, so that the chip component 6 can be attached closer to the resistor layer 5 side. Therefore, the distance between the wiring conductor layer 4 and the wiring conductor layer 3 on which the other electrode 6B is placed and fixed becomes small, and the area of the thick film circuit ES board can be reduced accordingly.

FIG. 2 is a process diagram for explaining an example of the manufacturing process of the thick film circuit board explained in FIG. 1. Note that the symbols used in FIG. 1 are used as they are.

First, as shown in FIG. 2(a), a solid insulating substrate 1 made of an insulator such as alumina is prepared. This insulating substrate 1 is screen printed using a silver-palladium conductor paste, and after drying, it is baked in the atmosphere at a profile of about 1 hour and a peak temperature of 850°C, as shown in Figure 2(b). A wiring conductor layer 2.3.4 is formed.

Next, as shown in FIG. 2C, a resistor layer 5 is screen printed between the formed wiring conductor layers 2.3 using a rudenium oxide resistor base and dried. And Fig. 2(d)
As shown in FIG. 3, a silver-palladium conductor paste (copper paste may also be used) is applied to the terminal portion 5a of the resistor layer 5 which has just been dried. An I terminal portion 8 is formed. In this forming step, the same RF firing process as that of the dried resistor layer 5 can be performed.

Next, as shown in FIG. 2(e), solder paste 7-. Print or apply 7'.

Thereafter, the chip component 6 is mounted on the solder paste 7' and soldered by reflow soldering, thereby completing the mounting of the chip component 6.

In this manner, the upper layer terminal portion 8 according to this embodiment can be formed simultaneously with the resistor layer 5, so that the problem of an increase in the number of steps does not occur.

In the above embodiment, only one electrode 6A of the chip component 6 is stacked on the terminal portion 5a of the resistor layer 5, but in the case of a chip component that bridges two resistor layers, The configuration of this embodiment may be applied to both electrodes 6A and 6B. Further, it is also applicable to a platform in which chip components 6 are connected in parallel to the resistor layer 5.

FIG. 3 is a sectional view on the J side showing another embodiment of a thick film circuit Lt board using copper-based conductor paste as the material for the wiring conductor layer. For thick film circuit boards using copper-based conductor paste,
First, the resistor layer 11 is formed, and the wiring conductor layers 12, 13, and 16 are formed so as not to change the resistance value. Therefore, the wiring conductor layer in this type of thick film circuit board is formed as the upper conductor layer of the formed resistor layer 11, as shown in FIG. Here, 12.13 is a wiring conductor layer formed for the resistor layer 11, and electrode forming portions 12a and 13 having a two-layer structure at both ends of the resistor layer 11.
You will have to turn a to the right. In this embodiment, the electrode forming section 1
The chip component 15 is soldered 1 using the electrode forming part 13a for mounting the chip component 15 among 2a and 13a.
4.14. Note that 16 is a wiring conductor layer for the other electrode 15B of the chip component 15, and 10 is an insulating substrate.

FIG. 4 is a process diagram showing an example of the manufacturing process of the thick film circuit board shown in FIG. 3.

FIG. 4(a) corresponds to FIG. 2(a). This insulating substrate 1
0, a resistor layer 11 is formed as shown in FIG. 4(b).

Next, as shown in FIG. 4(C), on the insulating substrate 10, the distribution FA conductor fM12,
Form 13.16. This is done by screen printing using a copper paste baked at a low temperature, dried at 120°C for 10 minutes, and then printed at a low temperature such as 600°C for 30 minutes at a low temperature such that the resistance value of the formed resistor layer 11 does not change. , and burnout in a nitrogen atmosphere.

FIG. 4(e) shows the same state as FIG. 3, in which the solder paste 14' printed on the electrode forming part 13a and the wiring conductor layer 16 in the previous step (FIG. 4d) is used to make the chip. Part 15
are soldered.

In this way, a thick film circuit board using a copper-based conductor paste can be constructed more easily than a thick-film circuit board using a silver-palladium-based conductor paste, and as in the embodiment shown in FIG. Since one electrode 15A of No. 15 can be placed on the electrode forming portion 13a of the resistor layer 11,
The effective mounting space for the chip component 15 can be narrowed.

Although each of the above embodiments has been described with respect to a single-sided thick film circuit board, it can of course be applied to a double-sided board as well as a multilayer board by repeatedly forming an upper layer conductor on a resistor layer, thereby reducing the manufacturing process. The invention can be applied without increasing the number.

(Effects of the Invention) As explained above, according to the present invention, the electrode forming portion of the resistor layer can be efficiently shared as a mounting space for chip components, so that chip components can be mounted at a higher density. It has the effect of contributing to high-density mounting on thick film circuit boards.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing one embodiment of a thick film circuit board according to the present invention, FIG. 2 is a process diagram illustrating an example of the manufacturing process of the substrate of FIG. 1, and FIG. 4 is a process diagram illustrating an example of the manufacturing process of FIG. 3, and FIG. 5 is a sectional view showing an example of a conventional thick film circuit board. 1.10 ...Insulating substrate, 5.11...Resistor layer, 6.15...Chip component, 8 (12a, 13a)...Upper FJ'jE element part (electrode forming part). Agent Patent Attorney Noriyuki Uji Hiroshi 8Yonarimo S Rein (Self, TA4Bene J) Figure 1 Figure 3 Figure 2 Figure 4

Claims (1)

[Scope of Claims] A resistor layer formed on an insulating substrate; An upper conductor portion for a resistance terminal formed as an upper layer conductor of this resistor layer and forming two layers together with the resistor layer; This upper layer conductor portion A thick film circuit board comprising a chip component on which an electrode part is placed and fixed.