Generally, many companies use thin silicon wafers to produce light and ultra-thin solar cells. These ultra-thin semiconductor wafers have many advantages over conventional ones. Not only are they easy to manufacture, but also it is more economical to mass-produce. So, many companies and manufacturers prefer to use thin-film silicon solar cells. Also, thinning of fully processed IC wafers has become a widely used technique in the search for high speed in advanced package technologies.
Reasons to develop Ultra-thin wafers:
Increase demand for a low package height for chip cards. Search for Systems in a Pack (SiP) using chip stack methods. Also for the requirement for a higher power.
These are advantageous to chip stack technology, high speed, and increased power.
Back grinding is a conventional method that reduces wafer thickness. Back grinding is suitable for the final packaging of dye after dicing. Grinding is fast and produces low variation and excellent surface finishes. For new, emerging applications that use the ultra-thin d, grinding remains the standard thinning method, but some process modifications and additional techniques are required.
This method is modified in three ways to remove grinding damage and improve the final surface finish.
2. Traditional loose-abrasive polishing
This method typically integrates a polishing step into the grinder itself, a technique that offers the advantage of combining the damage removal into the grinder tool and builds upon traditional CMP (chemical-mechanical-polishing) technology. CMP, however, has the disadvantage of low removal rates and perpetuates the surface profile.
3. Wet Etching
The wet Etching method or spin etching uses simple processes to remove surface damage. Wet chemical etching is one of the most popular thinning techniques. In this etching, an etching agent is moved periodically on the surface of one side of the rotating wafer. The surface is protected by applying special chucks. These chucks help to make thin wafers without using surface protection layers or tapes.
4. Dry Plasma Etching
This method uses atmospheric dry plasma etching to remove surface damage. This method offers the advantage that the surface damage is removed, the edges are improved by rounding the sharp corner, and the surface roughness can be controlled for adhesion.
2. Environmentally friendly.
3. Low energy payback time.
4. Temperature dependence is low
5. A little amount, i.e., a fractional amount of Pure Silicon, is needed for Manufacturing.