JPS62156801A - Manufacture of thin film chip resistor - 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 [Field of Industrial Application] The present invention relates to a thin film chip resistor that can be used in electronic equipment.

[Summary of the invention]

The present invention relates to a thin film chip resistor in which the protective film for the resistor film is constructed of a polyimide having an already imidized backbone, different from the high temperature curing polyimide precursor form, in which case the thickness is reduced to 0. It is constructed by coating with a thickness of 5 μm to 3 μm and baking this at 200° C. to 300° C.

〔Example〕

Hereinafter, a method for manufacturing a thin film chip resistor according to the present invention will be sequentially explained using the drawings.

First, as shown in FIG. 1, a heat-resistant and electrically insulating substrate (1) made of alumina or the like is provided, and a plurality of V-shaped grooves (2a) and (2b) extending vertically and horizontally are formed on the bottom surface of the substrate (1).
) to form. The interval between the 6 grooves (2a) is the length in the longitudinal direction of the resistor, for example, 3.21 mm, and the interval between the 6 grooves (2a) is the length in the longitudinal direction of the resistor.
The interval b) corresponds to the width of the resistor, and is, for example, 1.6 mm.

The entire upper surface of such a substrate (1) is coated with NlCr or T.
Deposit a resistive film (metal film) (3) such as aN! It is deposited by ivy or the like, and then a metal film (4) which becomes an electrode is also deposited.

Next, as shown in Figure @2, the electrode metal film (4) in the part corresponding to the intermediate part between the grooves (2r) and (2a) is removed from the groove (2a).
) is removed by etching along the extending direction of the groove (2a), thereby leaving the electrode metal film (4) in a band shape only in the portion corresponding to the groove (2a) so as to extend along the extending direction of this groove (2a). .

Thereafter, although not shown, the resistive film (3) is left in the required shape by etching or trihanging.

That is, the required resistance value is set. As this step, a tripping method using a radar beam or the like is used.

Next, as shown in FIG.
Coating.

In this case, as a material for the protective film (5), a photosensitive polyimide having an already iridized skeleton (for example, Ube Industries Co., Ltd.'s P
I-400)'f is used, and this is 0.5 μm to 3 μm.
Covers within the range of . In this case, the polyimide can be made into a uniform surface by using the so-called spin code method. The protective film (5) is pre-dried at a temperature of 60° C. for 30 minutes, and then a mask is used to dry the protective film (5) except for the portion that corresponds to the electrode metal film (4). Expose to light at a light intensity of 2 to 0.5 to harden this area.

Thereafter, it is developed for 30 seconds to 2 minutes to remove the unexposed portion of the protective film (5). FIG. 4 shows this state, whereby the above-mentioned bipolar metal film (4) is exposed.

After exposing the electrode metal film (4) in this way, the entire structure is cleaned with alcohol, and then a protective film (5) is applied at a temperature of 250''C for about 1 hour.

Next, the substrate (1)'t is folded using its groove (2a) to obtain a plurality of strips (6). FIG. 5 shows one of these strips (6). As is clear from this, the electrode metal films (4) are formed in pairs on both ends, and in FIGS.
They will be referred to as W (4a) and (4b).

As shown in FIG. 6, a full metal strip such as N1 (6
), and the terminals (7a) and (7b
) and eggplant. When forming these terminals (7 colors) and (7b) 1, the parts other than those to be formed should be plated in advance to electroless plate Ni, and then electroplated with Cu, Ni, and other metals by electroplating. Deposit metal. Since this process is conventionally well known, detailed explanation thereof will be omitted. With this, the terminal (7a) is connected to the 'electrode (4m
) and the terminal (7b) are electrically connected to the electrode (4b), respectively.

After the terminals (7a) and (7b) are formed in this way, they are bent and cut along the grooves (2b) previously formed on the bottom surface of the substrate (1) to form individual thin film chip resistors. Get a body.

The humidity-resistant load life of the resistor manufactured in this way was determined in a test chamber at a temperature of 40°C and a humidity of 95°C, at a rated DC voltage of 95°C.
While repeating the process of adding flow for 0 minutes and cutting flow 1 for 30 minutes, we measured the change in resistance value.
The results shown in the figure were obtained. In the figure, the horizontal axis is a scale of time, and the vertical axis is a scale of change rate of resistance value (ΔV illusion).
Select 5, 2.0 (each #l) and test each. In Fig. 7, when the film thickness is 0.1 am, the curve ia is 0.8, 1.5, 2.0 (each μm
).

As a result, a relatively large change over time was observed when the protective film (5) had a film thickness of 0.1 μm, but
In the case of No. m, there was hardly any change in resistance over time, and the resistance value also hardly changed, and it was confirmed that the resistance value was extremely stable.

〔Effect of the invention〕

According to the present invention described above, it is possible to obtain a thin film chip resistor with extremely stable resistance value and rate of change in resistance value.

[Brief explanation of drawings]

1 to 6 show an example of the manufacturing process of the thin film chip resistor according to the present invention, and FIG. 1 shows the resistance value and T
FIG. 2 is a perspective view of a portion of the electrode metal film with a part of it covered, FIG. 3 is a cross-sectional view of the entire surface with a protective film coated, and FIG. Figure 4 is a cross-sectional view with a portion of the protective film removed, and Figure 5 is a cross-sectional view of the groove (2&
) A perspective view showing an example of a strip obtained by folding along
FIG. 6 is a sectional view of the completed resistor, and FIG. 7 is a characteristic diagram of the humidity resistance load life test of the resistor thus obtained. (1) is the substrate, (3) is the resistive film, (5) is the retention tI film,
(7m) (7b) is a terminal.

Claims (1)

[Claims] A resistive film is attached onto an insulating substrate, and after etching or trimming the resistive film into a predetermined shape, heat treatment is performed to stabilize the resistance value and temperature characteristics. A protective film of 0.5 μm made of a photosensitive polyimide having an already imidized skeleton, which is different from the high-temperature curing polyimide precursor type, is applied on the insulating substrate.
A method for producing a thin film chip resistor, characterized by coating the resistor with a thickness of ~3 μm and curing it at a post-baking temperature of 200°C to 300°C.