HF + KOH = KF + H2O

---> Fail


An isotropic silicon etchant is HNA - HF + Nitric acid + Acetic acid -
but you need LP-CVD silicon nitride as a mask.

The easiest methods, in my humble opinion, to "drill through" a
silicon wafer, are DRIE, laser ablation and powderblasting.
Powderblasting is the cheapest of these, and works reasonably well.
Laser ablation is the fastest, but for 1mm diameter holes you need
trepenning, not simple drilling. And trepanning optics + sufficiently
powerful nano or picosecond laser = ExpensivE


m

On 12/9/10, Nabhiraj Yalagoud  wrote:
> kapton is not attacked by HF. So u can use kapton as mask and etch HF.
> Kapton is also not attacked by KOH.
>
> both etchants you can use separately as two different methods. There may be
> little lateral seepage, but when we are talking about 1 mm hole, you may get
> 1.1 mm, it should not matter much. Glue used in Kapton tape, is not easily
> etched by KOH.