MANUFACTURING METHOD OF SEMICONDUCTOR DEVICE

摘要

forming a first thermal oxide film(42) on a single crystalline silicon substrate(40); forming a photoresist(44) thereon, and forming a potoresist pattern to expose it to a light by a conventional photolithograpic process; etching the first thermal film(42) by dry etching, and removing the remained resist(44); forming an element isolating region(46) to selectively etch the substrate(40) by a reactive ion etching process, and removing the first thermal oxide film(42) by chemical etching process; forming a second thermal oxide film(48) over the surface; forming a first nitride film(50) thereon by a low pressure CVD; forming a BPSG(52) over the surface, and prefoming planarization under water vapor atmosphere; remaining the BPSG(52) to about 3000-5000 aug. thickness by etch back process; forming a oxide film(54) and a second nitride film(56) over the surface in turn; forming a insulating film(58) with good step coverage on the second nitride film(56) by plasma CVD process; and removing the second nitride film(56) by mechanical chemical polishing process, and preforming the insulating film(58); removing the second nitride film(56) and the thin oxide film(54) by chemical etching process. The nitride film and the CVD oxide film are completely insulated by automatic doping by B or P atoms in BPSG film. Accordingly the element isolating characteristic is improved.