Resistors｜Basic
SMD Resistor ＜Chip Resistor Structure＞
table of contents
Resistor Manufacturing Flow Example
The following illustrates the manufacturing flow of a typical SMD Resistor (MCR Series).
In actuality the entire alumina substrate is processed at one time, but for illustrative purposes only one chip will be shown.
What is Screen Printing?
Each layer of a ROHM chip resistor is formed by screen printing. Screen printing involves creating a print pattern on the mesh surface of a screen mask, then applying paste, then transferring the pattern onto a target object (alumina substrate) by scraping the paste with a squeegee.
Screen Printing Flow
Laser trimming
The Need for a Laser Trimming Process
Screen printing is used to form each layer of a thick film chip resistor and involves placing paste on the alumina substrate. Hundreds of chips are processed at the same time, inevitably leading to slight variations in printing conditions (i.e. paste thickness).
This results in varying resistance values, making it impossible to ensure optimum resistances. Therefore, an additional process is required to adjust the resistance values to within specified tolerances.
The Laser Trimming Process
A laser cuts the resistive element while the resistance is measured in order to achieve target resistance values with minimal variation. Laser trimming narrows the current pathway, which increases resistance. Once the target resistance has been met the laser is stopped to reduce variations between chips.
【Download Documents】 Resistor Design Basics Every Engineer Should Know
Resistor Design Basics Every Engineer Should Know An introductory handbook on practical resistor design for current limiting, voltage division, and current sensing, with concise explanations of basic structures, key ratings, TCR, and reliability.
Resistors
Basic
-
What is a Resistor?
- Resistor Basics
- Outline of a Resistor
- Shunt Resistors ＜Current Sence Shunt Resistors＞
- SMD Resistor ＜Chip Resistor Structure＞
- Chip Resistor Specifications
- What is Rated Voltage?
- High Power Guarantee Using Terminal Temperature Derating
- Temperature Coefficient of Resistance ①
- Temperature Coefficient of Resistance ②
- Temperature Coefficient of Resistance (TCR) Calculation Tool
- Usage exceeding the rated power
- Effects of Board Design on TCR (Shunt Resistors)
- Factors that Affect TCR ①
- Factors that Affect TCR ②
- Factors that Affect TCR ③
- Factors that Affect TCR ④
- Chip Resistor Failure Modes
- Current Sense Resistor ＜Advantages of Reverse-Mount Low-Ohmic Resistors＞
- Destruction Due to Overload