Why Gold Evaporation Materials Spit During Evaporation?
Evaporation is a physical vapor deposition (PVD) process whereby material is transformed into the vapor phase using thermal energy to enable a thin-film deposition on a substrate, often a wafer. It is a key technology employed to manufacture devices such as power amplifiers used in wireless handsets and high brightness light-emitting diodes (LEDs). Gold is one of the principal materials evaporated. Unfortunately, it can be prone to a behavior known as spitting. Spitting involves the ejection of liquid droplets from the molten pool of metal instead of the smooth transfer of material through evaporation.
A certain fraction of these liquid droplets land on the deposition wafer, where they solidify into solid particles. These particles constitute a defect since they can lead to the improper functioning of a microelectronic circuit. Spitting, therefore, negatively affects yield due to the scrapping of partial or whole production lots. Many factors can affect spitting and can be divided into two broad groups:
1) Process conditions and material quality.
2) Process conditions include power input, heat transfer, crucible liner user, E-Beam sweep pattern, ramp profiles, and deposition rates.
Material quality is determined by both purity and cleanliness.
AEM Deposition excels at providing too high purity gold evaporation materials (minimum of 99.999% purity) that have been deactivated and cleaned to the highest standards and can substantially reduce spitting and significantly increase our customers’ yield. Furthermore, AEM Deposition can help customers develop an understanding of the critical process parameters that can also be adjusted to minimize the likelihood of spitting.
AEM Deposition is a leading evaporation materials supplier, we provide all kinds of Metal, Oxide, Alloy, and Compounds evaporation materials for our customers, powder, pieces, and pellets are optional.