Plasma surface treatment can greatly improve packaging reliability

　　At present, the trend of assembly technology is mainly SIP, BGA, CSP packaging to make semiconductor devices develop in the direction of modularization, high integration and miniaturization. In such packaging and assembly processes, the problems are organic contamination at the bonding filler and oxide film formed during electric heating. Due to the presence of pollutants on the bonding surface, the bonding strength of these components is reduced and the potting strength of the resin after packaging is reduced, which directly affects the assembly level and continued development of these components. In order to improve and improve the assembly capacity of these components, every effort is made to deal with them. Improvement Practice has proved that the appropriate introduction of plasma surface treatment equipment for surface treatment in the packaging process can greatly improve the reliability of packaging and improve the yield rate.

Plasma is usually called the fourth state of matter. The first three states are solid, liquid, and gas. They are relatively common and exist around us. Although ions are very abundant elsewhere in the universe, they only exist in certain specific environments on Earth. The natural existence of ions includes lightning and northern lights. Just as it takes energy to convert solids into gases, it also takes energy to produce ions.

When the temperature rises, the substance changes from solid to liquid, and the liquid changes to gas. When the temperature of the gas rises, the gas molecules will separate into atoms. If the temperature continues to rise, the electrons surrounding the nucleus will separate from the atoms to form ions (positive charge) and electrons (negative charge). This phenomenon is called "ionization". Gas with charged ions due to ionization is called "plasma". Therefore, plasma is usually classified as the "fourth state" besides the physical states of "solid", "liquid" and "gas" in nature.

Plasma surface treatment equipment mainly uses low-pressure gas glow plasma. Some non-polymerizable inorganic gases (Ar2, N2, H2, O2, etc.) are excited at high frequency and low pressure to produce a variety of active particles including ions, excited molecules, free radicals, etc. In general, in plasma cleaning, activated gases can be divided into two categories, one is the plasma of inert gas (such as Ar2, N2, etc.); the other is the plasma of reactive gas (such as O2, H2, etc.). The principle of plasma generation is as follows: a set of electrodes is applied with radio frequency voltage (frequency is about tens of megahertz), a high-frequency alternating electric field is formed between the electrodes, and the gas in the area is excited by the alternating electric field to generate plasma. The active plasma performs a dual effect of physical bombardment and chemical reaction on the surface of the object to be cleaned, turning the surface material of the object to be cleaned into particles and gaseous substances, which are discharged through vacuum to achieve the cleaning purpose.