Sansan Consortium New Technology Presentation Meetings!
R-TPJ is adopted as EBR process of semiconductor

October 13rd, 2022, “Sansan Consortium New Technology Presentation Meetings!” was held by online method. In this here, an oral presentation of Professor. Higashi (Hiroshima University) is picked up.

Fig.1 Image of R-TPJ method

The research group proposed to highly remained etch photo resist film in edge of silicon wafer as EBR (Edge Bead Removal) by Reactive Atmospheric-pressure Thermal Plasma Jet (R-TPJ) method.

As figure 1, R-TPJ is irradiated with an organic film such as photo resist film in atmosphere environment by the DC arc charge using Ar + O2 gas, as a result, this film is dry-etched. In EBR process, it's possible to etch top and bottom plane at the same time by introduction of 2 units.

Compared to the conventional atmospheric-pressure plasma method, etching rate is greatly higher because of making aggressive use of thermal, which is generated by plasma charge. In the past, Ag gas only was used, however, O2 gas was used recently, too. As a result, etching rate was increased to 10.1 μm/s. This is reason why ashing effect functionates in addition to etching because of generation of active species (O^※) of oxygen atom. By the way, etching rate of conventional atomospheric-pressure plasma method is approximate 4 μm/min as a whole.

Etching rate is mainly influenced by O2 flow rate (fo2) and work distance. In proportion to value of the former, etching rate is increased. Picture 1 shows images of photo resist samples before and after R-TPJ irradiation. In case of O2 flow ratio = 1.0 L/min, maximum etching rate was obtained.

Pic.1 SEM images of photo resist samples

On the other hand, in proportion to narrowing of the later, etching rate was increased. This is reason why high temperature annealing effect by plasma is considered to be caused.