JPH04365302A - Thin film resistor capable of functional trimming - Google Patents

Abstract

PURPOSE:To facilitate functional trimming, by applying a photosensitive resin to resistor films on an insulation base board as a protective film. CONSTITUTION:Using a ceramic base board 1 as an electrically insulating base board, resistor films 3 and primary electrode films 4 are formed on the base board 1 by a deposition method. After forming patterns by a photoetching method, a heat treatment is performed, and the resistance values of the resistor films 3 are trimmed by laser trimming. Then, on the base board 1, a photosensitive polyimide film 2 of a cold cure type is formed by a spin coat method. Successively, the electrode parts 4 are exposed by exposing the photosensitive film 2 and by developing it, and they are cured by post baking. Thereby, the product comprising the resistor films can maintain its characteristic resistant to environments and its mechanical strength, and it is made possible to perform a functional trimming from above the film 2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film resistor used in electronic equipment.

0002

2. Description of the Related Art In order to perform functional trimming using a laser beam, it is necessary that a resistive film be exposed.

0003

[Problems to be Solved by the Invention] In order to perform functional trimming using a laser beam, the resistive film must be exposed, but in general, with thin film resistors, if the resistive film is exposed, the resistance The resistance value tends to change due to environmental and mechanical influences, which causes deterioration in the performance of the resistor. Due to the characteristics of the resin, it is difficult to make a protective coating film made of epoxy resin or phenol resin into a state where it can be functionally trimmed with a laser beam. Furthermore, resins that do not have photosensitivity cannot be selectively processed into protective films.

0004

[Means for Solving the Problems] The present invention involves forming a resistive film deposited on the surface of an insulating substrate into a predetermined shape and resistance value, and then coating the insulating substrate containing the resistive film with photosensitive polyimide, exposing it to light.
After exposing only the necessary parts through development processing, the film is heated and cured. By using photosensitive polyimide as a protective film, the environmental resistance and mechanical strength of the product can be maintained, and functions can be trimmed from above the film.

[0005]

Example 1 Thin Film Network Resistor In this example, a ceramic substrate measuring 50 mm x 60 mm and having a thickness of 0.635 mm was used as the electrically insulating substrate. A nickel-chromium-based resistance film and a primary electrode film were deposited on the substrate by vapor deposition, patterned by photoetching, heat treated at 350° C. for 1 hour, and the resistance value was adjusted by laser trimming. The specifications of this product are 6KΩ 3 elements,
±10 ppm/°C. Next, a low-temperature curing photosensitive polyimide is applied to the substrate to a thickness of about 2 μm by spin coating. This was exposed to light and developed to expose the electrode portion, and then post-baked at 300° C. for 1 hour to harden it. Next, the board was divided into modules, leads were inserted and soldered, and the product shown in FIG. 1 was completed. The functional trimming area can be adjusted in the range of 0 to 4KΩ.

[0006]

[Example 2] Thin film resistance temperature sensor In this example, the electrically insulating substrate is 50mm x
A ceramic substrate having a diameter of 60 mm and a thickness of 0.635 mm was used. A nickel film was deposited on the substrate by vapor deposition, and a pattern was formed by photoetching, followed by heat treatment at 320° C. for 1 hour. The specifications of this product are approximately 70Ω, approximately +5
000 ppm/°C. Next, a low-temperature curing photosensitive polyimide is applied to the substrate to a thickness of about 2 μm by spin coating. This was exposed to light and developed to expose the electrode portion, and then post-baked at 300° C. for 1 hour to harden it. Next, the board was divided into elements and soldered to complete the product shown in FIG. 2. Functional trimming area is 0
Adjustment is possible in the range of ~50Ω.

[0007]

[Example 3] Thin film chip resistor In this example, the electrically insulating substrate is 50 mm x
A ceramic substrate with a diameter of 60 mm and a thickness of 0.4 mm was used. A nickel-chromium-based resistive film and a primary electrode film were deposited on the substrate by sputtering, patterned by photoetching, heat treated at 350° C. for 1 hour, and the resistance value was adjusted by laser trimming. The specifications of this product are 2.
0Ω, ±10 ppm/°C. Next, a low-temperature curing photosensitive polyimide of approximately 2 μm was applied to the substrate by spin coating.
Apply at a film thickness of . This was exposed to light and developed to expose the electrode portion, and then post-baked at 300° C. for 1 hour to harden it. Next, the secondary electrode was formed and divided by plating, and the product shown in FIG. 3 was completed. Functional trimming area is 0
Adjustment is possible in the range of ~30Ω.

[0008]

[Effects of the Invention] According to the present invention, it has become possible to manufacture a resistor that can be functionally trimmed and has environmental resistance and mechanically stable characteristics.

[0009]

[Brief explanation of drawings]

FIG. 1 is a top view showing a thin film network resistor manufactured by the manufacturing method of the present invention.

FIG. 2 is a top view showing a thin film resistance sensor manufactured by the manufacturing method of the present invention.

FIG. 3 is a top view showing a thin film chip resistor manufactured by the manufacturing method of the present invention.

[Explanation of symbols]

1. Ceramic substrate 2. Photosensitive polyimide film 3. Nickel chromium-based resistive film 4. Solder electrode 5. Primary trimming area 6. Functional trimming area 7. Nickel-based resistive film 8. Plating electrode

Claims (1)

[Claims] Claim 1: In a thin film resistor consisting of a resistive film and electrodes deposited on the surface of an insulating substrate such as a ceramic, the resistive film is coated with a photosensitive resin as a protective film to enable functional trimming. A thin film resistor characterized by: