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This section provides an overview for mask roms as well as their applications and principles. Also, please take a look at the list of 6 mask rom manufacturers and their company rankings. Here are the top-ranked mask rom companies as of December, 2024: 1.Macronix International Co., Ltd, 2.IBS Electronics, 3.Minato Advanced Technologies Inc.
Table of Contents
A mask ROM is a type of read-only memory (ROM) where the memory content is predetermined during the manufacturing process at a semiconductor plant.
In semiconductor memory classification, ROM falls into two categories: mask ROM and programmable ROM. Unlike programmable ROMs, mask ROMs cannot be erased or rewritten after manufacturing.
Mask ROMs are cost-effective for mass production and prevent unauthorized rewriting of programs post-shipment. However, they pose challenges for post-manufacturing modifications due to the lengthy development and manufacturing periods.
Mask ROMs, being immutable once shipped, find applications as fixed data memory for control programs in embedded devices, microcode for CPUs, game software, kanji fonts, dictionary data, and more.
Due to the inability to easily correct bugs post-production, programmable ROMs are often used during system development, with the finalized data then sent to a memory manufacturing facility to produce mask ROMs.
Mask ROMs come in two main structures: NAND type and NOR type. The NAND type features transistors connected in series, while the NOR type has transistors connected in parallel. Both types consist of a grid of word lines and bit lines, with each memory cell represented by a transistor.
The data is written to the mask ROM during the semiconductor wafer fabrication process. Each transistor's content is set to 1 or 0 during this process, and once written, the data remains unchanged.
To read data, the word line connected to the cell to be read is activated, and the other word lines are deactivated. The current in the bit line connected to the cell is then detected, with a current indicating a 1 and no current indicating a 0.
Mask ROMs employ three methods for writing data: diffusion, contact, and ion implantation.
Applicable to the NOR type, where only transistors with data 1 are formed on the wafer, omitting transistors with data 0. However, it sees limited use due to the extended manufacturing time.
Also applicable to the NOR type, this method involves not connecting the source of transistors with data 0 to the bit line. Its manufacturing time is shorter as it depends on whether contact holes connecting transistors and wiring are made in the latter half of the wafer process.
Compatible with both NAND and NOR types, this method implants ions into transistors to alter their threshold voltages. Transistors with relatively high threshold voltages are set to 0, while those with low threshold voltages are set to 1.
Aside from mask ROMs, EEPROM and flash memory are also available as ROM types, each with its advantages and disadvantages.
This ROM type allows users to rewrite its contents. It can be used for both reading and writing operations without special procedures, making it suitable for recording computer configuration information.
Flash memory enables easy writing and erasing of data, with contents retained even when power is off. Commonly used in memory cards and USB flash drives for storing data.
Lower production costs compared to flash memory and EPROM. Simpler peripheral circuits and cell structures result in high integration levels among semiconductor memories.
Initial costs for mask development are required. The manufacturing process takes several days to a month to start mass production. Altering recording contents necessitates remaking the mask, and program updates like bug fixes are challenging.
*Including some distributors, etc.
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Rochester Electronics, LLC is a manufacturer stocking distributor of end-of-life semiconductors and the broadest range of active semiconductors that is headquartered in Newburyport, Massachusetts, and was founded in 1981. The company caters to manufacturing services ranging from design, wafer processing, testing, reliability, and IP Archiving. These specifically include OCM, build-to-order products, process flows, and standard packaging creation. The company pivots on manufacturing and distributing semiconductors that are no longer produced by its original manufacturer.
IBS Electronics was established in 1980 in Southern California. It is an ISO 9001: 2008 certified authorized franchise distributor and chain supplier to electronic manufacturers. They specialize in providing a wide range of products, including semiconductors, passive components, connectors, and electromechanical parts. They serve various industries such as aerospace, automotive, medical, telecommunications, and consumer electronics. These are used in industries that rely on electronic components for a wide range of applications, such as in aircraft and spacecraft systems, automotive electronics, medical devices, communication infrastructure, and consumer electronic devices.
Macronix International Co. Ltd., founded in 1989 and headquartered in the Science Park of Hsinchu, Taiwan, is an integrated device manufacturer in the NVM (non-volatile memory) market. The company's product portfolio includes a range of NOR flash, NAND flash, and ROM products. It has expanded its offerings with 19-nanometer NAND flash and eMMC (trademarked) product families designed for embedded applications demanding higher reliability and also offers a Known Good Die for System In Package (SIP) solutions. Its product design support comprises technical documents, reference designs, and software support.
Minato Advanced Technologies Inc., founded in 2018 (a split from Minato Holdings Inc.) and headquartered in Kanagawa, Japan, is a manufacturer of device programmers and a provider of ROM programming services for manufacturing equipment and production environments. Its hardware product portfolio comprises universal gang programmers, automated programmers, and device programmer peripherals that support ICs (integrated chips) such as microcontrollers, eMMCs, and EPROMs. These products and devices are often used in industrial and commercial settings, including manufacturing, healthcare, and automotive, to automate processes and improve efficiency.
Flexxon Pte Ltd, founded in 2007 and headquartered in Singapore, is a manufacturer and designer of industrial NAND flash storage and memory devices. The company offers an array of product portfolio, which includes SATA III, PATA, PCIe, memory cards, USB, and more. It has expanded its product line to introduce the X-PHY brand, featuring the world's first AI-embedded firmware-based cybersecurity solution. These devices serve various sectors such as cybersecurity, industrial, medical, and automotive (CIMA) applications, providing compact memory storage solutions.
Leshan Radio Company Ltd. (LRC), established in 1971 and headquartered in Leshan with new factories and R&D centers in Chengdu, China, is a manufacturer of semiconductor devices that has grown into a group company with several subsidiary and JV companies. The company's core product portfolio includes diodes, transistors, and MOSFETs, and more recently, it has expanded production into ESD protection devices and ICs. These products have applications for industrial electronics, home appliances, and telecommunication products across its 5,000+ client base and sales across 100+ countries and regions.
Ranking as of December 2024
Derivation Method| Rank | Company | Click Share |
|---|---|---|
| 1 | Macronix International Co., Ltd |
33.1%
|
| 2 | IBS Electronics |
23.4%
|
| 3 | Minato Advanced Technologies Inc |
15.3%
|
| 4 | Rochester Electronics |
13.7%
|
| 5 | Flexxon Pte Ltd |
8.1%
|
| 6 | LRC Co., Ltd |
6.5%
|
Derivation Method
The ranking is calculated based on the click share within the mask rom page as of December 2024. Click share is defined as the total number of clicks for all companies during the period divided by the number of clicks for each company.Number of Employees
Newly Established Company
Company with a History
*Including some distributors, etc.
*Including some distributors, etc.
| Country | Number of Companies | Share (%) |
|---|---|---|
|
United States of America
|
2 | 50.0% |
|
Taiwan
|
1 | 25.0% |
|
Japan
|
1 | 25.0% |
Silicon Device Co., Ltd.
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