JPH03153105A - Trimming method for resistive terminator - Google Patents

Abstract

PURPOSE:To prevent an extreme current concentration from being caused onto a resistance film by forming a wide spread part expanding partially the width of a strip resistance film in advance to a resistive terminator used for a microwave circuit and matching a resistance between electrodes with a reference value while the wide spread part is being cut gradually. CONSTITUTION:A wide spread part 4a spreading locally the width is formed to one side in the middle of the beltlike resistance film 4. While the resistance between the electrodes 2 and 3 is being measured, the wide spread part 4a is gradually cut by a laser trimming device and the resistance is accurately matched to the reference value. Since a cut part 5 exists in the wide spread part 4a in this way, the width of the resistance film 4 is not extremely made narrow. Thus, no extreme current concentration is caused in the resistance film, resulting that the resistive terminator with a high dielectric strength is easily realized in a limited component size.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a non-reflection terminator used in a microwave circuit, and more particularly to a trimming method for accurately adjusting the resistance value between electrodes to a reference value.

(Prior Art) Figures 4(A) and 4(B) show typical structures of non-reflection terminators. The rectangular parallelepiped-shaped substrate 1 is made of ceramics such as alumina, ferrite, beryllia, and aluminum nitride. Two electrode parts 2 and 3 are formed on the substrate 1 using a highly conductive metal material such as gold, silver, or copper. Electrode portions 2 and 3 are formed at opposite ends of the upper surface of the substrate 1, and a resistive film 4 is formed in a strip shape between the electrode portions 2 and 3. As the material for the resistive film 4, tantalum nitride, Nichrome 11, etc. are used in the case of a thin film, and ruthenium oxide, silver-baladium alloy, etc. are used in the case of a thick film. At the stage of forming the resistive film 4, the resistance value between the electrode parts 2 and 3 is designed to be slightly smaller than the reference value (50Ω).

At almost the final stage of the manufacturing process, while measuring the resistance value between the electrode parts 2 and 3, a laser trimming device or the like is used to measure the resistance value shown in Figure 4 (
C) Partially remove the resistive film 4 as shown in (D).
(deleted part) Adjust the resistance value exactly to the reference value.

(Problems to be Solved by the Invention) As shown in FIG. 4, in the conventional non-reflection terminator, the resistive film 4
is formed into a strip of uniform width, and is locally removed in the width direction by trimming. Therefore, the width of the resistive film 4 at the portion where the deleted portion 5 is formed becomes extremely narrow, and the current is concentrated in that narrow portion. There is no problem if the current value is small, but when used in a high-power microwave circuit, a relatively large current flows through the resistive film 4 of the non-reflective terminator, and if that current is concentrated in a portion, the element may overheat. and destroy it.

In other words, with conventional trimming methods, it is difficult to realize a high-power-resistant, non-reflection terminator with limited element dimensions.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to provide a method for trimming a non-reflective terminator so as to prevent extreme current concentration from occurring in the resistive film.

(Means for Solving the Problems) Therefore, in the present invention, the width of the resistive film is locally enlarged.
．． A widened portion was formed in advance, and this widened portion was gradually removed so that the resistance value between the electrode portions matched the base value.

(Function) Since the resistance value is adjusted while removing the widened portion formed on the resistive film, the width of the trimmed portion does not become narrower than other portions, and the current concentration point is No cow.

(Example) Figure 1 (A) shows the state before trimming of a non-reflective terminator according to an example of the present invention (7). 1 is a substrate, 2 and 3 are electrode parts, and 4 is a resistive film. The material is as described above.The feature of this embodiment is that the j;)-shaped resistive film 4
The width is locally expanded on one side of the middle part of the
Form a and be at the point. SoL-CFigure 1 (B) (
As shown in C), after measuring the resistance value between the electrode parts 2 and 3, the widened part 4a of the resistive film 4 is gradually removed using a laser trimming device or the like to accurately match the resistance value to the reference value. , 15 indicates a portion where the resistive film 4 has been removed by trimming. In this way, since the deleted portion 5 is located in the widened portion 4a,
Resistance lI! 2! , The part where the width of 4 is extremely narrow occurs.
-No.

FIG. 2 shows a second embodiment of the present invention, with (A) before trimming and (B) after trimming. In this embodiment, two widened portions 4a, 4)) are formed in advance on both ends of the resistive film 4, and removed portions 5 are formed by trimming on these widened portions 4a, 4b.

FIG. 3 shows various examples of the widened portions 4a, 4k formed in the resistive film 4.

(Effects of the Invention) As explained in detail below, in the trimming method of the non-reflective terminator of the present invention, the resistance value is adjusted to the reference value while removing the widened portion of the resistive film that has been formed in advance. Even if a portion is removed by trimming, there will be no portion where the width of the resistive film becomes extremely narrow.

Therefore, extreme current concentration does not occur in the resistive film, and as a result, a non-reflection terminator with high power resistance can be easily realized using the limited termination=J- method.

[Brief explanation of the drawing]

FIG. 1(A) is a plan view of a non-reflective terminator before trimming according to an embodiment of the present invention, FIG. 1(B) and (C) are plan views of a non-reflective terminator after trimming, and FIG. ) is a plan view of the non-reflection terminator before trimming according to the second embodiment of the present invention,
Figure (B) is a plan view of the non-reflection terminator after l-rimming.
FIGS. 3(A) to 3(C) are plan views showing various backings of the resistive film formed with the widened portion according to the present invention, and FIG. 4(A)
) is a plan view of conventional unreflected q, trimming of tp terminal equipment] 1ij, the same figure (B) is the west + Jxj figure, the same figure CC) (D
) is the "I4 side view" after trimming. ・Substrate...Electrode section...Resistance film 4b...Width section...Removed section by shirring 1...3 4...A 5...

Claims (1)

[Claims] In a non-reflective terminator in which a resistive film is formed in a strip shape between two electrode parts formed on a substrate, a widened part is formed in advance by locally enlarging the width of the resistive film, and this widened part is A method for trimming a non-reflective terminator, comprising adjusting the resistance value between the electrode portions to a reference value while gradually removing the electrode portions.