“Wafers are indispensable components in many Electronic devices. In order to improve everyone’s understanding of wafers, this article will introduce wafers based on two points: 1. Wafer foundry, 2. Wafer back-end manufacturing process introduction.

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Wafers are indispensable components in many electronic devices. In order to improve everyone’s understanding of wafers, this article will introduce wafers based on two points: 1. Wafer foundry, 2. Wafer back-end manufacturing process introduction.

Wafer refers to the silicon wafer used to make silicon semiconductor circuits, and its raw material is silicon. High-purity polysilicon is dissolved and mixed with silicon crystal seeds, which are then slowly pulled out to form cylindrical monocrystalline silicon. The silicon ingot is ground, polished and sliced ​​to form a silicon wafer, that is, a wafer. At present, domestic wafer production lines are mainly 8 inches and 12 inches.

1. Wafer foundry

Today’s chips such as CPU and GPU are all cut from wafers. A large wafer can be cut into many chips. The closer to the center of the circle, the theoretically the better the quality. low. What is foundry? In the simplest terms, it is to help others produce wafers.

At present, the well-known foundries are probably TSMC, GF, UMC, SMIC, Samsung, Intel, etc.; some of them are specialized in foundry, such as TSMC, UMC, GF, SMIC; some are integrated Chip design, chip manufacturing, chip packaging and testing and other industrial chain links are integrated, such as Samsung and Intel. These companies can not only produce wafers themselves, but also provide foundry services for other Fabless.

We are familiar with the processing workshop, which uses various equipment to send customers the wheat and rice that need to be processed into flour, rice and so on. This eliminates the need for everyone who needs to process food to build a workshop. Our current foundry is like a fab. Wafer foundry is to provide specialized manufacturing services to professional integrated circuit design companies or electronic manufacturers. This business model enables integrated circuit design companies to produce without having to undertake expensive factories themselves. This means that foundries such as TSMC distribute the huge risk of building factories to a broad customer base and diversified products, thereby focusing on the development of more advanced manufacturing processes.

With the development of semiconductor technology, the investment required for wafer foundry is also increasing. Now the most commonly used 8-inch production line, the investment to build one needs 1 billion US dollars. Still, many foundries invested a lot of money and purchased a lot of equipment. This is enough to show that the foundry will achieve great development in the near future, and the proportion of the global semiconductor industry will also increase day by day.

2. Wafer back-end production process

1. Packaging process

A single die is fixed on a plastic or ceramic chip base, and some lead terminals etched on the die are connected to the pins protruding from the bottom of the base to connect with the external circuit board, and finally Cover with plastic cover and seal with glue. Its purpose is to protect the die from mechanical scratches or high temperature damage. Only then can an integrated circuit chip (Integrated Circuit; IC for short) be made.

2. Test process InitialTestandFinalTest

The last process of chip manufacturing is testing, which can be divided into general testing and special testing. The former is to test the electrical characteristics of the packaged chip in various environments, such as power consumption, operating speed, and withstand voltage. The tested chips are divided into different grades according to their electrical characteristics. The special test is to take out some chips from similar parameter specifications and varieties according to the technical parameters of the special needs of customers, and do targeted special tests to see if they can meet the special needs of customers, so as to decide whether to design special chips for customers. chip. Products that have passed the general test are labeled with specifications, models, and date of manufacture, and can be shipped after being packaged, while chips that fail the test are classified as downgraded or discarded depending on the parameters they achieve.