JPS6165464A - Manufacture of film resistor in thick film multilayer substrate - Google Patents

Abstract

PURPOSE:To facilitate the trimming of the resistor of the lower circuit layer by a method wherein the interlayer insulation layer at the part opposed to the part of trimming of the lower circuit layer is formed thinly in manufacture of the titled substrate. CONSTITUTION:The lower layer wiring conductors 28 and 29 and the lower layer resistor 30 are formed on an insulation substrate 27 of alumina or the like. Next, interlayer insulation layers 32 and 33 are formed, and the upper wiring conductors 35, 36, and 37 and the upper layer resistor 38 are formed on the insulation layer 33. At this time, the part of the insulation layer 33 opposed to the part of trimming of the lower resistor 30 is provided with an aperture 34, and the insulation layer is thinned at this part. Then, the laser output does not have to be much increased in trimming 40 to the lower layer resistor 30, and trimming is facilitated; besides, its time is saved. Since the lower layer resistor 30 can be subjected to trimming after calcination of the upper layer circuits, the resistance value of the lower layer resistor 30 can be accurately set.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a method for manufacturing a film resistor on a thick film multilayer substrate, and in particular, it facilitates trimming of a resistor formed on the lower layer side. This invention relates to a device that allows the resistance value of the device to be set accurately.

C. Technical Background of the Invention] As is well known, in recent years, hybrid integrated circuits have come into widespread use in order to reduce the size and weight of electronic devices and the like. This hybrid integrated circuit generally consists of a thick film substrate on which a circuit layer is formed by printing a conductive material and a resistive material on an insulating substrate, and a single chip-type passive element or active element without lead wires is soldered to the thick film substrate. It is composed of

By the way, in the thick film substrate as described above, in order to achieve high-density packaging of circuits, circuit layers are formed in multiple layers with insulating layers interposed therebetween.

FIG. 3 is for explaining a conventional manufacturing method of such a thick film multilayer substrate. First, lower layer wiring conductors 12 and 13 and lower layer resistor 14 are formed on insulating substrate 11 made of a ceramic material such as alumina to constitute first circuit layer 15. The lower wiring conductor 12.13 is formed, for example, by printing a silver-palladium paste using a screen printing method and firing it in an oxidizing atmosphere at a high temperature of 800 to 900°C. In addition, the lower layer resistor 14
is formed, for example, by printing and firing a ruthenium oxide paste in the same manner as above. Then, the lower resistor 14 is trimmed (notches 16) by, for example, a laser trimming method or a sandblasting method.
to set its resistance value.

Thereafter, printing and baking of, for example, a glass-based paste is repeated twice on the first circuit layer 15 to form a two-layer insulating layer 17.
．． 48, and the upper layer wiring conductors 19 to 21 and the upper layer resistor 22 are formed on the insulating layer 18 on the upper side in the figure in the same manner as described above to constitute the second circuit layer 23. Then, the upper layer resistor 22 is trimmed (cuts 24) to set its resistance value, thereby constructing a thick film multilayer substrate.

[Problems with Background Art] However, in the conventional thick film multilayer substrate manufacturing method as described above, after trimming of the lower resistor 14 is completed, that is, after the resistance value of the lower resistor 14 is set, the insulating layer 17 is
．． 18, upper layer wiring conductors 19 to 21, upper layer resistor 22, etc., firing at high temperatures is repeated, so there is a problem that the resistance value of lower layer resistor 14 varies greatly from the setting value at the time of trimming. arise. In particular, since the fluctuation range of this resistance value can reach as much as about 10%, the lower layer resistor 14 has the disadvantage that it cannot be applied to circuits that require a highly accurate resistance value. It is. Further, since the trimming process for the lower layer resistor 14 and the trimming process for the upper layer resistor 22 are performed separately, there is also a problem that the manufacturing process becomes complicated.

Therefore, in recent years, the method shown in Fig. 4 (Japanese Patent Laid-Open No. 5
9-9997) is being considered.

That is, this means that the first circuit layer 15 . without trimming after forming the lower resistor 14 . After the insulating layers 17, 18 and the second circuit layer 23 are all formed, the lower resistor 14
For example, a laser beam is irradiated onto the insulating layer 18 to perform trimming (notches 25), and the upper layer resistor 22 is also trimmed (notches 26).

However, with the above-mentioned means, the two-layer insulating layer 17.
Since the film thickness of the entire resistor 18 is usually 40 to 50 μm, there is a problem in that it is technically extremely difficult to trim the lower resistor 14 through the insulating layer 17, 18. For example, when performing laser trimming, the laser output must be increased and the trimming speed must be reduced, which is extremely time consuming and results in poor resistance accuracy compared to direct trimming. It is.

[Object of the Invention] The present invention has been made in consideration of the above circumstances, and has the aim of accurately setting the resistance value of the resistor formed on the lower layer side without changing it, and also simplifying the manufacturing process. The purpose of this invention is to provide a method for manufacturing a film resistor using a good thick film multilayer substrate.

[Summary of the Invention] That is, the method for manufacturing a film resistor in a thick film multilayer substrate according to the present invention includes a first step of forming a first circuit layer including a resistor on an insulating substrate; After the step, a second step of forming an insulating layer on the first circuit layer by reducing the film thickness of a portion facing the trimmed portion of the resistor;
After this second step, a third step of forming a second circuit layer on the insulating layer; and after this third step, trimming the resistor through a thin portion of the insulating layer. By providing a fourth step of performing the above, it is possible to accurately set the resistance value of the resistor formed on the lower layer side without changing it and to simplify the manufacturing process. .

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. 1 and 2, first, an insulating substrate 21 made of a ceramic material such as alumina, etc.
Lower layer wiring conductors 28 and 29 and lower layer resistor 30 are formed on top to form a first circuit layer 31. The lower wiring conductors 28 and 29 are formed, for example, by printing a silver-palladium paste using a screen printing method and firing the paste at 800 to 900° C. in an oxidizing atmosphere. Further, the lower layer resistor 30 is formed, for example, by printing and baking a ruthenium oxide paste in the same manner as described above.

Thereafter, without trimming the lower resistor 30, printing and firing of, for example, a glass-based paste is repeated twice on the first circuit layer 31 to form a two-layer insulating layer 32.
form 33. In this case, the upper insulating layer 33 in the figure is
It is formed to have an opening 34 at a position corresponding to the trimmed portion of the lower resistor 30, and as a result, the insulating layer 32, 33
The combined thickness of the lower resistor 30 is made thinner in the portion corresponding to the trimmed portion of the lower resistor 30.

Then, upper layer wiring conductors 35 to 37 and upper layer resistor 38 are formed on the insulating layer 33 in the same manner as described above to constitute a second circuit layer 39. Thereafter, the lower layer resistor 30 is trimmed (cut 40) through the opening 34 of the insulating layer 33, and at the same time, the upper layer resistor 38 is also trimmed (cut 41), and the thick film multilayer substrate is composed of

Therefore, according to the above embodiment, the first circuit layer 31.
The second circuit layer 39, insulating layers 32, 33, etc. are all printed/printed.
After firing, the lower resistor 30 is trimmed, and since the combined thickness of the insulating layers 32 and 33 is thinner in the portion corresponding to the trimmed portion of the lower resistor 30, trimming can be done easily and the lower resistor 30 can be trimmed. The resistance value of the resistor 30 can be set accurately, and it can be used in circuits that require highly accurate resistance values.

Further, since the lower layer resistor 30 and the upper layer resistor 39 can be trimmed at the same time, the trimming process is only performed once, and manufacturing is simplified.

Here, in the above embodiment, the resistor 30.38 is formed in both the first circuit layer 31 and the second circuit 1i139, but this means that the resistor 30 is formed only in the first circuit layer 31. Needless to say, the present invention can also be applied to those with a multilayer structure of three or more layers of low antibodies. Further, the openings 34 formed in the insulating layer 33 may be appropriately set, for example, in an L-shape or a circular shape, and a plurality of openings may be formed for one lower layer resistor.

In other words, instead of forming the opening 34 in the insulating layer 33, an opening may be formed in the insulating layer 32 to reduce the combined thickness of the insulating layers 32 and 33. Furthermore, the present invention is not limited to the high-temperature firing type thick-film multilayer substrate as described above, but can also be applied to a resin-based low-temperature curing type thick-film multilayer substrate.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without departing from the gist thereof.

E Effects of the Invention] Therefore, as detailed above, according to the present invention, it is possible to accurately set the resistance value of the low antibody formed on the lower layer side without changing it, and the manufacturing process can also be simplified (
This makes it possible to provide a method for manufacturing a film resistor in a thick film multilayer substrate that is superior in quality.

[Brief explanation of the drawing]

1 and 2 are a side sectional view and a plan view, respectively, showing an embodiment of the method for manufacturing a film resistor in a thick film multilayer substrate according to the present invention, and FIGS. FIG. 2 is a side sectional view showing a method for manufacturing a film resistor in a multilayer substrate. 11... Insulating substrate, 12.13... Lower layer wiring conductor,
14... Lower layer resistor, 15... First circuit layer, 16
...Cut, 11°18...Insulating layer, 19-21
...Upper layer wiring conductor, 22...Upper layer resistor, 23...
・Second circuit layer, 24...notch, 25.26...
- Notch, 27... Insulating substrate, 28. 29... Lower layer wiring conductor, 30... Lower layer resistor, 31... First circuit layer, 32. 33... Insulating layer, 34... ·Aperture,
35-37... Upper layer wiring conductor, 38... Upper layer resistor, 39... Second circuit layer, 40.41... Notch.

Claims (2)

[Claims] (1) A first step of forming a first circuit layer including a resistor on an insulating substrate, and a portion facing the trimmed portion of the resistor on the first circuit layer after this first step. a second step of forming an insulating layer by thinning the film thickness; a third step of forming a second circuit layer on the insulating layer after this second step; A method for manufacturing a film resistor in a thick film multilayer substrate, comprising: a fourth step of trimming the resistor through a thin portion of the insulating layer. (2) In the second step, a plurality of insulating layers are formed in multiple layers, and an opening is formed in a portion of a predetermined insulating layer that faces the trimmed portion of the resistor, thereby increasing the thickness of the entire insulating layer. 2. A method of manufacturing a film resistor in a thick film multilayer substrate according to claim 1, wherein the film resistor is made thinner.