Semiconductor Sputtering: What Is This Process and Why ...

Semiconductors undergo numerous processes to achieve functional status for various applications. One of those processes is sputtering, a technique employed across many industries. But what exactly is sputtering, and why is it integral to the semiconductor field?

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The process of semiconductor sputtering involves depositing thin films of material onto a substrate. This technique plays a crucial role in several applications within the semiconductor industry, such as the creation of device contacts, the formation of resistors and capacitors, and the manufacturing of transistors. Let's delve into the details of semiconductor sputtering and its significance in semiconductor fabrication.

What Is Sputtering?

Sputtering refers to the process by which surface atoms are ejected from a solid target material upon being bombarded by energetic ions. For sputtering to occur, the kinetic energy of the incoming ions must exceed the binding energy of the target material's surface. This method is classified as physical vapor deposition and creates a thin film on either the sputtering target material or the substrate, generally within a vacuum chamber. The average number of target atoms released for every incident ion is termed the sputter yield.

In simpler terms, sputtering involves bombarding a material with particles that carry energy, typically in the form of plasma or inert gas. This collision results in the ejection of particles from the surface of the solid material under bombardment. Conventional thermal energies during this process must remain lower than the energetic ion bombardment impacting the material. While sputtering can occur naturally in space, humans have effectively applied it within a multitude of terrestrial applications.

Various types of sputtering exist—including DC sputtering, which utilizes direct current, as well as magnetron sputtering, reactive sputtering, and RF sputtering. The capability to execute sputtering on thin film materials has been pivotal in the development of a wide range of devices and equipment, spanning from nanotechnology materials to semiconductor devices and optical material coatings.

We will now explore the specifics of sputtering in the semiconductor realm, from the execution of the process to its relevance and potential drawbacks.

The Sputtering Process In The Semiconductor Industry

The demand for sputtering target materials in semiconductor manufacturing is substantial, as they are essential for various stages in the wafer fabrication process, including the application of conductive and barrier layers. The sputtering method also finds usage in semiconductor chip packaging.

Ion beam sputtering for etching in semiconductors and reactive sputtering is among the primary sputtering techniques employed. The question arises: why is sputtering so critical in the realm of semiconductors?

The Importance Of Sputtering Targets For Semiconductors

The rapid advancement of technology and increasing consumer expectations for lightweight devices with improved efficiency and processing capabilities necessitate enhancements to sputtering techniques and targets employed in semiconductor manufacturing.

Sputtering plays a vital role in both wafer fabrication and chip packaging. However, semiconductors are highly sensitive components that require exceptional purity in both wafer and chip production due to their susceptibility to surface contamination. Meeting consumer expectations means that the quality of sputtering target materials must be exceptional, typically at a purity level of 99.99% (5N5) or higher.

The effectiveness of the sputtering process is closely linked to the quality of metal target materials. High-quality materials significantly impact various facets of semiconductor fabrication, such as the uniformity and conductive performance of the conduction and barrier layers. Consequently, these factors influence the momentum transfer and stability of chip transmissions.

Numerous types of sputtering target materials and evaporation materials are employed in semiconductor fabrication, which we will discuss comprehensively below.

Sputtering Target Materials For Semiconductors

A wide range of elements can function as sputtering target materials when bombarded by high-energy particles. These materials come in different purity levels and forms—ranging from monoblocks to various compounds—and differ in the cathode materials and mounting methods they utilize. Each sputtering target caters to specific use cases and is only viable in designated sputtering target systems with particular coating materials.

Below are some common elements used in this context, though it’s important to note that not all may be applicable across all applications:

• Aluminium
• Chromium
• Copper
• Gold (g), (g)
• Molybdenum
• Nickel
• Niobium
• Palladium (g), (g)
• Platinum
• Quartz
• Silicon
• Silver
• Titanium
• Tungsten

The Drawbacks Of Semiconductor Sputtering/Etching

While sputtering presents numerous advantages, it is not without its drawbacks. This physical process requires top-of-the-line sputtering equipment and high-purity target materials to safeguard the silicon wafer or other wafer materials from rapid damage.

Wafer Damage

If sputtering occurs outside controlled conditions or employs subpar sputtering targets, it is likely to leave a film on the wafer. This can lead to short circuits or irreparable damage to the circuits.

High Voltage Use

The sputtering process demands considerable ion energy, making it quite taxing to initiate and sustain.

High-Quality Semiconductor Components For Your Devices

Sputtering and etching are vital processes in semiconductor device fabrication. Throughout this discussion, we have explored what sputtering entails and how it operates within the semiconductor landscape. Furthermore, we've noted that sputter deposition is a critical step in producing high-quality semiconductors, while sputter etching enhances device efficiency. Although there are some disadvantages associated with sputtering technology—namely wafer damage and high voltage requirements—the benefits of faster processing and superior quality products far outweigh these issues.

At Acetron Technologies, we supply high-quality semiconductor manufacturing equipment sourced from respected manufacturers in South Korea. If you're interested in learning more about our products and services, please reach out.

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FAQs

Why is the sputtering process used?

Sputtering is extensively utilized within semiconductor fabrication for forming thin layers of materials essential to integrated circuit processing. This technology is also employed to create optical antireflection coatings on glass for a variety of applications.

What are the advantages of RF sputtering?

RF magnetron sputtering presents a significant advantage over DC magnetron sputtering in that it does not necessitate an electrically conductive target. This revolutionary technique theoretically allows for the sputter deposition of any material.