What is a Target Material

The coating target material is a sputtering source that forms various functional films on the substrate through magnetron sputtering, multi arc ion plating, or other types of coating systems under appropriate process conditions. Simply put, the target material is the target material bombarded by high-speed charged particles, used in high-energy laser weapons. When different power densities, output waveforms, and wavelengths of lasers interact with different target materials, they will produce different killing and destruction effects. For example, evaporative magnetron sputtering coating is a heating evaporation coating, aluminum film, etc. By replacing different target materials (such as aluminum, copper, stainless steel, titanium, nickel targets, etc.), different film systems (such as superhard, wear-resistant, anti-corrosion alloy films, etc.) can be obtained.

The general uses of the target material include:

1. Maintain and improve the surface properties of materials, such as hardness, wear resistance, corrosion resistance, etc;

2. Used to prepare new materials or improve the performance of existing materials, such as solar cells, LEDs, flat panel displays, etc;

3. Used for preparing electronic components, such as transistors, integrated circuits, etc;

4. Used for preparing materials such as superconductors, optical thin films, sensors, etc.

Various types of sputtered thin film materials have been widely used in semiconductor integrated circuits (VLSI), optical disks, flat panel displays, and surface coatings of workpieces. Since the 1990s, the synchronous development of sputtering target materials and sputtering technology has greatly met the needs of the development of various new electronic components. For example, in the manufacturing process of semiconductor integrated circuits, copper conductor films with lower resistivity are used instead of aluminum film wiring. In the flat panel display industry, various display technologies (such as LCD, PDP, OLED, and FED) have developed synchronously, and some have been used in the manufacturing of computer and computer displays; In the information storage industry, the storage capacity of magnetic memory is constantly increasing, and new magneto-optical recording materials are constantly emerging. These have put forward higher requirements for the quality of sputtering targets required, and the demand for quantity is also increasing year by year.

Among all application industries, the semiconductor industry has the most stringent quality requirements for target sputtering films. Nowadays, 12 inch (300 orifice) silicon wafers have been manufactured, while the width of interconnections is decreasing. The requirements of silicon wafer manufacturers for target materials are large size, high purity, low segregation, and fine grain size, which requires the manufactured target materials to have better microstructure. The diameter and uniformity of crystalline particles in the target material have been considered as key factors affecting the deposition rate of thin films. In addition, the purity of the thin film is closely related to the purity of the target material. In the past, copper targets with a purity of 99.995% (4N5) may meet the needs of semiconductor manufacturers in the 0.35pm process, but they cannot meet the current 0.25um process requirements. However, for the 0.18um or even 0.13m process, the required target purity will be required to reach 5 or even 6N. Compared to aluminum, copper has higher resistance to electromigration and lower resistivity, which can meet the requirements! The need for submicron wiring with conductor technology below 0.25um has brought about other problems: low adhesion strength between copper and organic dielectric materials, and easy reaction, leading to corrosion and open circuit of copper interconnects in the chip during use. To address these issues, a barrier layer needs to be installed between the copper and the dielectric layer. Barrier layer materials generally use metals and their compounds with high melting points and high resistivity, so it is required that the thickness of the barrier layer be less than 50nm and have good adhesion performance with copper and dielectric materials. The barrier materials for copper interconnects and aluminum interconnects are different. New target materials need to be developed. The target materials used for the barrier layer of copper interconnects include Ta, W, TaSi, WSi, etc. However, Ta and W are all refractory metals, making them relatively difficult to manufacture. Currently, research is being conducted on titanium alloys such as molybdenum and chromium as alternative materials.