Patent ID: 8124543

Claim:
A method to form a semiconductor laser diode, comprising steps of: forming a striped structure including a semiconductor stack having a plurality of semiconductor layers; covering said striped structure with an inorganic layer containing silicon; burying said striped structure and said inorganic layer by a resin so as to make a top surface of said resin planar, said resin containing silicon in a concentration; and forming an opening in said resin and said inorganic layer at a portion on said striped structure by a photo-resist as an etching mask, said photo-resist being free from silicon or containing silicon in a concentration less than said concentration in said resin, wherein said formation of said opening including steps of, etching said resin partially by a reactive ion etching with a mixed gas of CF 4 and O 2 under a first ratio of a partial pressure for said CF 4 to a partial pressure for O 2 , etching said photo-resist partially by said reactive ion etching with a mixed gas of CF 4 and O 2 under a second ratio of a partial pressure for CF 4 to a partial pressure for O 2 , said second ratio being less than said first ratio, etching said resin by said reactive ion etching with a mixed gas of CF 4 and O 2 under a third ratio of a partial pressure for CF 4 to said O 2 , said third ratio being greater than said second ratio, and etching said inorganic layer by said reactive ion etching with a mixed gas of CF 4 and O 2 under a fourth ratio of a partial pressure for CF 4 to a partial pressure for O 2 .