Resistor Composition Laser Trimming

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Solution Overview

Problem

Miniaturized and thinned resistors with complex shapes face challenges in maintaining uniform resistance values, requiring easy adjustment through laser trimming while ensuring hardness and adhesion to substrates.

Innovation Solution

A resistor composition comprising copper, nickel, and lanthanum boride with copper particles of 2.5 µm or more, along with inorganic components like silicon oxide and glass, facilitates easy laser trimming by maintaining a specific mass ratio and particle diameter distribution, enhancing resistance value adjustability and adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the resistor is miniaturized and thinned with complex shape, then the electronic device achieves miniaturization and high integration, but the resistance value varies and becomes difficult to control

Engineering Contradiction:
Improveresistor sizeVSAvoidresistance value uniformity
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent changes the physical and chemical parameters of the resistor material by specifying a particular composition ratio (copper 40-70 mass%, nickel 5-30 mass%, lanthanum boride 5-30 mass%) and copper particle size (2.5 μm or more) to enable laser trimming while maintaining miniaturization. This parameter optimization allows the small resistor to be adjusted after formation, resolving the contradiction between miniaturization and resistance value control.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If laser trimming is performed to adjust resistance value, then the resistance value can be precisely controlled, but the resistor material must be hard enough to withstand laser processing

Engineering Contradiction:
Improveresistance value adjustabilityVSAvoidmaterial hardness
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent uses a composite material system combining copper particles (for conductivity and laser response), nickel (for hardness and structural stability), and lanthanum boride (for adhesion and thermal stability). This composite formulation enables the resistor to be both hard enough for laser trimming and adjustable in resistance value, resolving the contradiction between hardness and adjustability.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If copper particles with diameter of 2.5 μm or more are used, then laser trimming becomes easier and resistance value can be adjusted, but the resistor may have reduced adhesion to substrate

Engineering Contradiction:
Improvelaser trimming easeVSAvoidadhesion to substrate
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent employs a composite material system where copper particles (≥2.5 μm) provide laser trimming responsiveness, while nickel and lanthanum boride components ensure adequate adhesion to the substrate. The synergistic combination of these materials resolves the contradiction between ease of laser trimming and adhesion strength.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different material functions to different aspects of the resistor: copper particles handle the laser trimming function, while the nickel and lanthanum boride matrix provides the adhesion function. This local quality differentiation allows the resistor to simultaneously achieve easy laser trimming and strong substrate adhesion.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The resistor composition allows for precise adjustment of resistance values with reduced variation, improved hardness for trimming, and enhanced adhesion, facilitating efficient laser trimming and stability on substrates.

Implementation Method 1

when the resistor is irradiated with a laser beam, copper particles having a particle diameter of 2.5 μm or more are likely to be shed, so laser trimming can be easily performed

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

the resistance value of the resistor can be increased

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP3506324B1Resistor, circuit board provided with same, and electronic device
Publication Date: 2021.05.19 KYOCERA CORP
  • EP3506324B1 patent drawingFigure 1~2

AI summary

A resistor according to the present disclosure includes copper, nickel, and lanthanum boride, a total content of which is 40% by mass or more, the resistor including copper particles having a particle diameter of 2.5 µm or more. In addition, a circuit board according to the present disclosure includes a substrate; the resistor described above, which is located on the substrate; a metal layer; and a glass layer located on the resistor. Further, an electronic device according to the present disclosure includes the circuit board described above; and an electronic component located on the metal layer of the circuit board.