Breakthrough in high-density 2.5D/3D integrated packaging technology: Successful case of embedded EMMC packaging products

This case study provides a detailed introduction to the successful development and industrial application of embedded EMMC packaging products based on advanced high-density 2.5D/3D integrated packaging technology. This product adopts a ball grid array (BGA) packaging form, innovatively achieving system level integration of the main control chip, NAND flash chip, and cache chip, and successfully completing an 8-layer FLASH chip stack to achieve ultra large storage capacity. The product has the convenient feature of "patch ready", with a complete set of intelligent management functions such as automatic bad block management, wear balance, power failure protection, and error correction verification, which can perfectly adapt to mainstream ARM chip architectures and Android, Linux operating systems. At present, this product has been widely used in mobile terminal devices such as smartphones, tablets, and learning machines, and has successfully entered the wearable device market such as smartwatches, smart bracelets, and AR glasses with its miniaturization advantage. It provides high reliability, high integration, and high cost-effectiveness local data storage solutions for various smart terminals, effectively promoting the development of the semiconductor packaging industry towards higher density and miniaturization.

1、 Project Background and Industry Challenges

With the rapid development of the global smart terminal industry, consumers have increasingly high requirements for the lightweight, portability, storage capacity, and operating speed of devices. The traditional discrete storage solution not only occupies a large amount of PCB board space, limiting the miniaturization design of terminal devices, but also has problems such as high signal transmission delay, high power consumption, and insufficient reliability. At the same time, with the popularization of mobile applications, high-definition audio and video, artificial intelligence and other technologies, the demand for local data storage capacity in intelligent terminals is growing exponentially. How to achieve larger storage capacity and better system performance in limited physical space has become a key technical challenge that urgently needs to be solved in the semiconductor industry.

In this context, high-density 2.5D/3D integrated packaging technology has become the core technology path to solve the above problems due to its ability to stack multiple chips vertically, significantly improve integration, and shorten signal transmission paths. However, multi-layer chip stacking technology faces many technical challenges, including chip alignment accuracy control during the stacking process, interlayer thermal management, signal integrity assurance, yield improvement, etc. To overcome these technological bottlenecks and meet the urgent market demand for high-performance and miniaturized storage products, we have launched a research and development project for embedded EMMC packaging products based on 2.5D/3D integrated packaging technology.

2、 Core technical architecture of the solution

This project adopts industry-leading high-density 2.5D/3D integrated packaging technology to build a complete embedded EMMC system level packaging solution. This solution breaks the traditional model of independent packaging of chips, integrating the originally separate main control chip, NAND flash chip, and cache chip into the same BGA package, achieving high integration of the storage system.

In terms of chip stacking technology, we have overcome the key technical challenges of precision stacking of multi-layer chips. By optimizing the bonding process and using high-precision bonding equipment, we have successfully achieved stable stacking of 8-layer NAND flash memory chips. This technological breakthrough has significantly increased the storage capacity of products by several times under the same packaging size, effectively solving the contradiction between the demand for large capacity storage in smart terminals and device miniaturization.

At the same time, we fully considered signal integrity and thermal management issues in the packaging design. By optimizing wiring design and using low dielectric constant materials, signal transmission delay and crosstalk have been effectively reduced, and data transmission rate has been improved. In terms of thermal management, we have adopted advanced heat dissipation materials and structural design to ensure that the heat generated by multi-layer chip stacking can be dissipated in a timely manner, ensuring the stability and reliability of the product under high load operation.

3、 Core advantages and technological highlights of the product

Ultra high integration and large storage capacity

The product adopts a ball grid array (BGA) packaging form, integrating the main control chip, NAND flash memory chip, and cache chip into one, greatly reducing the number of components and PCB board space occupation. By using 8-layer FLASH chip stacking technology, a large storage capacity has been achieved, which can meet the storage needs of intelligent terminals for systems, applications, and massive audio and video data.

The convenience of 'patch ready to use'

This embedded EMMC product is a complete storage subsystem that does not require any peripheral circuit support. Customers only need to directly mount the product onto the motherboard for use, greatly simplifying the design process of terminal devices, shortening the product development cycle, and reducing research and development costs and production difficulties.

Comprehensive intelligent management and protection functions

The product is equipped with a comprehensive intelligent management algorithm, including automatic bad block management, wear balance, power failure protection, and error correction verification functions. Automatic bad block management can detect and mark bad blocks in flash memory in real time, avoiding data writing errors; The wear balance algorithm effectively extends the service life of the product by evenly distributing the number of erasures and writes to each storage unit; The power-off protection function can ensure that the data being written is not lost and prevent file system damage in the event of a sudden power outage; The error correction and verification function can automatically detect and correct errors that occur during data transmission, ensuring the integrity and accuracy of the data.

Wide compatibility and adaptability

The product strictly follows industry standards and specifications, and can perfectly adapt to mainstream ARM chip architectures in the market, fully supporting mainstream operating systems such as Android and Linux. This enables the product to be quickly applied to various intelligent terminal devices without the need for extensive adaptation work, improving the product's versatility and market competitiveness.

4、 Diversified application scenarios and implementation effectiveness

The embedded EMMC packaging product, with its excellent performance and wide applicability, has successfully achieved large-scale industrial applications, covering multiple intelligent terminal fields.

In the field of mobile terminals, products have been widely used in devices such as smartphones, tablets, and learning machines to carry operating systems, various applications, and user data such as photos, videos, and documents. Its high reliability and large capacity characteristics provide users with a smooth user experience and sufficient storage space, which has been recognized and adopted by many well-known terminal manufacturers.

In the field of wearable devices, the advantages of miniaturized BGA packaging have been fully utilized. Wearable devices such as smartwatches, smart bracelets, and AR glasses have extremely strict requirements for size and weight, and traditional storage solutions are difficult to meet their design needs. Our embedded EMMC product has successfully solved the local data storage problem of wearable devices with its extremely small packaging size and lightweight design, achieving secure and reliable storage of sports data, health data, user information, etc., providing strong support for the expansion of wearable device functions.

As of now, the product has shipped tens of millions of units and its market share has steadily increased. The yield and reliability of the product have been rigorously tested through large-scale production and market applications, and all performance indicators have reached the international advanced level.

5、 Project Value and Industry Impact

The success of this project has not only brought significant economic benefits to the company and enhanced its core competitiveness in the semiconductor packaging field, but also made positive contributions to the development of China's semiconductor industry.

At the technical level, this project has broken through key technologies such as multi-layer chip stacking and system level integration, forming a series of core technological achievements with independent intellectual property rights, and promoting the development and industrialization process of high-density 2.5D/3D integrated packaging technology in China.

At the industrial level, the successful mass production and widespread application of this product have broken the monopoly of foreign manufacturers in the high-end embedded storage market, providing stable and reliable domestic storage solutions for domestic intelligent terminal manufacturers, reducing the dependence of the domestic terminal industry on imported chips, and enhancing the supply chain security of China's intelligent terminal industry.

At the market level, the launch of this product has enriched the market supply of domestic storage products, promoted market competition, pushed for the rationalization of storage product prices, and ultimately benefited a large number of consumers. At the same time, the successful application of the product in emerging fields such as wearable devices also provides important technical support for the rapid development of these emerging industries.

In the future, we will continue to increase our research and development investment in high-density 2.5D/3D integrated packaging technology, continuously improve our technological level, launch more high-performance and highly integrated packaging products, meet the growing market demand, and contribute greater strength to the high-quality development of China's semiconductor industry.