Development of a PECVD Tetraethylorthosilicate (TEOS) Fill Process for Shallow Trench Isolation

As transistors have decreased in size and increased in packing density, a need has arisen for an alternative to the LOCOS method of isolation. Shallow trench isolation (STI) offers superior packing density and stronger immunity to latch up with other side benefits. A TEOS oxide fill for STI is a good choice because its mobile chemical precursors offer a high level of conformality. A plasma enhanced deposition of this oxide allows for greater control over film characteristics. A designed experiment was created to examine the effects of temperature, RF power, and substrate position (measured through electrode spacing) on the oxide quality and fill ability. High quality oxide with void free fill ability was found with the processes conditions: temperature of 350C, RF power of 350W and electrode spacing of 225mils