Outsourced Semiconductor Assembly and Test | How Does OSAT Work

The semiconductor industry is a big part of modern technology. It powers everything from smartphones to powerful computers. As the need for chips grows, making them has become more complex. One important part of making chips is called OSAT. This means companies send their chips to other experts who package and test them. This helps save time and lets chip makers focus on what they do best. So in this guide, we will explain how it works, why it is important, and look at some major companies doing outsourced semiconductor assembly & testing, especially in India.

What is OSAT (Outsourced Semiconductor Assembly & Test)?

OSAT means hiring other companies to put together and check computer chips after they are made. These companies package the chips to protect them and test them to make sure they work well. This also helps chip makers save money, use the latest technology, and focus on what they do best.

The OSAT Process

It means hiring other companies to help put together and test computer chips. These companies handle important steps to make sure the chips work well and are ready to use.

1. Wafer Fabrication: Making a chip starts in a special factory where silicon wafers are turned into chips using light, chemicals, and other processes.
2. Dicing: After the chips are made on the wafer, the wafer is cut into tiny pieces each piece is one chip.
3. Packaging: These tiny chips are then placed in protective covers (called packages). So, they can be safely used in electronic devices.
4. Testing: The packaged chips are tested to make sure they work properly and can handle heat, pressure, and other stress.
5. Final Inspection: Before shipping, each chip is checked one last time to find and remove any that are broken.

What is the Role of OSAT in the Semiconductor Supply Chain?

It is very important in making computer chips. It helps chip companies work faster, save money, and make better products. Here are some simple ways it helps:

• Saving Money: Chip companies can save money by letting OSAT companies handle the assembly and testing. These companies do it faster and cheaper because they have better tools and experience.
• Focus on What They Do Best: Chip makers can focus on designing and making the chips, while OSAT companies take care of putting them together and checking if they work.
• Better Technology: OSAT companies use the newest machines and ideas. Chip makers benefit from this without having to build it themselves.
• Easy to Grow or Shrink: If chip demand goes up or down, OSAT companies can quickly make more or fewer chips. So, chip makers don’t need to buy new machines or buildings.
• Worldwide Help: OSAT companies work in many countries. This helps chip makers sell their chips all over the world and avoid problems if one place has issues.

OSAT plays a vital role in delivering efficient, cost-effective chip packaging and testing which is crucial for embedded devices. If you're curious about how such components power real-world systems, our Embedded Systems Course offers practical insights into microcontrollers, circuit design, and hardware-software integration.

OSAT Companies in India

India is becoming important in making computer chips. Some Indian companies help by doing OSAT work. OSAT means putting chips into cases (packaging) and checking if they work well (testing). So, here are some of the companies that do this:

1. Tata Elxsi

Tata Elxsi helps design and test chips. They generally work on chips used in cars, hospitals, and home gadgets.

2. Sankalp Semiconductor

Sankalp makes and tests chips. They make sure the chips are packed as well as they work properly.

3. STMicroelectronics

STMicroelectronics works in India and helps make and test outsourced semiconductor chip fab. They use smart ways to pack and check the chips.

4. NXP Semiconductors

NXP works in India too. They test and pack chips, mostly for cars and also for smart devices.

5. Qualcomm

Qualcomm is a big chip company. In India, they work on packing and testing chips for phones and wireless devices.

What is the Difference Between OSAT and ATMP in Semiconductor Fabs?

In making computer chips, two words are often used: OSAT and ATMP. They sound similar but are a little different.

OSAT:

• What it means: It’s when companies send their chips to other expert companies to pack and test them.
• Focus: Only on packaging and testing.
• Use: Helps chip makers get their chips ready after making them.

ATMP:

• What it means: It includes more steps - putting the chip together (assembly), testing it, adding labels (marking), and packing it.
• Focus: Covers all steps before the chip is sent out.
• Use: It is a wider process than OSAT.

Why this matters:
Knowing the difference helps chip companies choose the right partners and plan better.

Largest OSAT Company in the World

Based on the available data, here is an overview of the largest Outsourced Semiconductor Assembly and Test companies globally for 2024 and projections for 2025:

Industry Trends and Projections for 2025 

• Market Growth: The OSAT industry is growing fast. In 2023, it was worth about $43.37 billion, and by 2030, it could reach $74.78 billion, growing at about 8% per year.
• Asia Leads the Market: Countries like Taiwan, China, and the U.S. control more than 80% of the market, with most OSAT factories based in Asia.
• New Technologies: Companies are spending more money on advanced packaging techniques like 3D packaging, SiP (System-in-Package), and flip-chip to make chips smaller and more powerful.
• Big Partnerships: Companies are teaming up. For example, Amkor is working with TSMC to build a new factory in Arizona that will focus on advanced packaging for chips.

Top OSAT Semiconductor Companies in 2024