Why does a wafer box contain 25 wafers?

In the sophisticated world of modern technology, wafers, also known as silicon wafers, are the core components of the semiconductor industry. They are the basis for manufacturing various electronic components such as microprocessors, memory, sensors, etc., and each wafer carries the potential of countless electronic components. So why do we often see 25 wafers in a box? There are actually scientific considerations and the economics of industrial production behind this.

Revealing the reason why there are 25 wafers in a box

First, understand the size of the wafer. Standard wafer sizes are usually 12 inches and 15 inches, which is to adapt to different production equipment and processes. 12-inch wafers are currently the most common type because they can accommodate more chips and are relatively balanced in manufacturing cost and efficiency.

The number "25 pieces" is not accidental. It is based on the cutting method and packaging efficiency of the wafer. After each wafer is produced, it needs to be cut to form multiple independent chips. Generally speaking, a 12-inch wafer can cut hundreds or even thousands of chips. However, for ease of management and transportation, these chips are usually packaged in a certain quantity, and 25 pieces is a common quantity choice because it is neither too large nor too large, and it can ensure sufficient stability during transportation.

In addition, the quantity of 25 pieces is also conducive to the automation and optimization of the production line. Batch production can reduce the processing cost of a single piece and improve production efficiency. At the same time, for storage and transportation, a 25-piece wafer box is easy to operate and reduces the risk of breakage.

It is worth noting that with the advancement of technology, some high-end products may adopt a larger number of packages, such as 100 or 200 pieces, to further improve production efficiency. However, for most consumer-grade and mid-range products, a 25-piece wafer box is still a common standard configuration.

In summary, a box of wafers usually contains 25 pieces, which is a balance found by the semiconductor industry between production efficiency, cost control and logistics convenience. With the continuous development of technology, this number may be adjusted, but the basic logic behind it - optimizing production processes and improving economic benefits - remains unchanged.

12-inch wafer fabs use FOUP and FOSB, and 8-inch and below (including 8-inch) use Cassette, SMIF POD, and wafer boat box, that is, the 12-inch wafer carrier is collectively called FOUP, and the 8-inch wafer carrier is collectively called Cassette. Normally, an empty FOUP weighs about 4.2 kg, and a FOUP filled with 25 wafers weighs about 7.3 kg.
According to the research and statistics of the QYResearch research team, the global wafer box market sales reached 4.8 billion yuan in 2022, and it is expected to reach 7.7 billion yuan in 2029, with a compound annual growth rate (CAGR) of 7.9%. In terms of product type, semiconductor FOUP occupies the largest share of the entire market, about 73%. In terms of product application, the largest application is 12-inch wafers, followed by 8-inch wafers.

In fact, there are many types of wafer carriers, such as FOUP for wafer transfer in wafer manufacturing plants; FOSB for transportation between silicon wafer production and wafer manufacturing plants; CASSETTE carriers can be used for inter-process transportation and use in conjunction with processes.

Wafer Cassette (13)

OPEN CASSETTE
OPEN CASSETTE is mainly used in inter-process transportation and cleaning processes in wafer manufacturing. Like FOSB, FOUP and other carriers, it generally uses materials that are temperature-resistant, have excellent mechanical properties, dimensional stability, and are durable, anti-static, low out-gassing, low precipitation, and recyclable. Different wafer sizes, process nodes, and materials selected for different processes are different. The general materials are PFA, PTFE, PP, PEEK, PES, PC, PBT, PEI, COP, etc. The product is generally designed with a capacity of 25 pieces.

Wafer Cassette (1)

OPEN CASSETTE can be used in conjunction with the corresponding Wafer Cassette products for wafer storage and transportation between processes to reduce wafer contamination.

Wafer Cassette (5)

OPEN CASSETTE is used in conjunction with customized Wafer Pod (OHT) products, which can be applied to automated transmission, automated access and more sealed storage between processes in wafer manufacturing and chip manufacturing.

Wafer Cassette (6)

Of course, OPEN CASSETTE can be directly made into CASSETTE products. The product Wafer Shipping Boxes has such a structure, as shown in the figure below. It can meet the needs of wafer transportation from wafer manufacturing plants to chip manufacturing plants. CASSETTE and other products derived from it can basically meet the needs of transmission, storage and inter-factory transportation between various processes in wafer factories and chip factories.

Wafer Cassette (11)

Front Opening Wafer Shipping Box FOSB
Front Opening Wafer Shipping Box FOSB is mainly used for the transportation of 12-inch wafers between wafer manufacturing plants and chip manufacturing plants. Due to the large size of wafers and higher requirements for cleanliness; special positioning pieces and shockproof design are used to reduce impurities generated by wafer displacement friction; the raw materials are made of low-outgassing materials, which can reduce the risk of out-gassing contaminating wafers. Compared with other transport wafer boxes, FOSB has better air-tightness. In addition, in the back-end packaging line factory, FOSB can also be used for the storage and transfer of wafers between various processes.

Wafer Cassette (2)
FOSB is generally made into 25 pieces. In addition to automatic storage and retrieval through the Automated Material Handling System (AMHS), it can also be manually operated.

Wafer Cassette (9)Front Opening Unified Pod

Front Opening Unified Pod (FOUP) is mainly used for the protection, transportation and storage of wafers in the Fab factory. It is an important carrier container for the automated conveying system in the 12-inch wafer factory. Its most important function is to ensure that every 25 wafers are protected by it to avoid being contaminated by dust in the external environment during the transmission between each production machine, thereby affecting the yield. Each FOUP has various connecting plates, pins and holes so that the FOUP is located on the loading port and operated by the AMHS. It uses low out-gassing materials and low moisture absorption materials, which can greatly reduce the release of organic compounds and prevent wafer contamination; at the same time, the excellent sealing and inflation function can provide a low humidity environment for the wafer. In addition, FOUP can be designed in different colors, such as red, orange, black, transparent, etc., to meet process requirements and distinguish different processes and processes; generally, FOUP is customized by customers according to the production line and machine differences of the Fab factory.

Wafer Cassette (10)

In addition, POUP can be customized into special products for packaging manufacturers according to different processes such as TSV and FAN OUT in chip back-end packaging, such as SLOT FOUP, 297mm FOUP, etc. FOUP can be recycled, and its life span is between 2-4 years. FOUP manufacturers can provide product cleaning services to meet the contaminated products to be put into use again.

Contactless Horizontal Wafer Shippers
Contactless Horizontal Wafer Shippers are mainly used for the transportation of finished wafers, as shown in the figure below. Entegris's transport box uses a support ring to ensure that the wafers do not contact during storage and transportation, and has good sealing to prevent impurity contamination, wear, collision, scratches, degassing, etc. The product is mainly suitable for Thin 3D, lens or bumped wafers, and its application areas include 3D, 2.5D, MEMS, LED and power semiconductors. The product is equipped with 26 support rings, with a wafer capacity of 25 (with different thicknesses), and wafer sizes include 150mm, 200mm and 300mm.

Wafer Cassette (8)


Post time: Jul-30-2024
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