Semiconductor device having semiconductor circuit formed by semiconductor elements and method for manufacturing the same

A method for manufacturing a semiconductor device comprising the steps of:

• forming a gate electrode over a substrate;
• forming a gate insulating film over the gate electrode and forming a semiconductor film over the gate insulating film without exposing to the atmosphere;
• forming an insulating film over the semiconductor film;
• forming a first mask over the insulating film;
• introducing a first impurity element into the semiconductor film by using the first mask;
• forming a second mask so as to overlap with a first part of the first mask, and in contact with a part of the insulating film and the first part of the first mask to expose a second part of the first mask;
• introducing a second impurity element into the semiconductor film by using the second mask to form an LDD region and a source or drain region, the second part of the first mask doped with the introduced second impurity element;
• and
• forming an interlayer insulating film over the first mask and the second mask,
• wherein the LDD region is in contact with one end of a channel formation region, and one of the source and drain region is in contact with the other end of the channel formation region.

A method for manufacturing a semiconductor device comprising the steps of:

• forming a gate electrode over a substrate;
• forming a gate insulating film over the gate electrode and forming a semiconductor film over the gate insulating film without exposing to the atmosphere;
• forming a first insulating film over the semiconductor film;
• forming a second insulating film over the first insulating film;
• forming a first mask over the second insulating film;
• introducing a first impurity element to the semiconductor film by using the first mask;
• forming a second mask so as to cover a first part of the first mask, and in contact with a part of the insulating film and the first part of the first mask to expose a second part of the first mask;
• introducing a second impurity element into the semiconductor film by using the second mask to form an LDD region and a source or drain region;
• and
• forming an interlayer insulating film over the first mask, and in contact with the second part of the first mask, the second mask, and the insulating film,
• wherein the LDD region is in contact with one end of a channel formation region, and one of the source and drain region is in contact with the other end of the channel formation region.

A method for manufacturing a semiconductor device comprising the steps of:

• forming a gate electrode over a substrate;
• forming a gate insulating film over the gate electrode and forming a semiconductor film over the gate insulating film without exposing to the atmosphere;
• forming a first insulating film over the semiconductor film;
• forming a second insulating film over the first insulating film;
• forming a first mask over the second insulating film;
• introducing a first impurity element into the semiconductor film by using the first mask;
• forming a second mask so as to cover a first part of the first mask, and in contact with a part of the second insulating film and the first part of the first mask to expose a second part of the second mask;
• introducing a second impurity element into the semiconductor film by using the second mask to form an LDD region and a source or drain region, the second part of the first mask doped with the introduced second impurity element;
• and
• forming an interlayer insulating film over the first mask and the second mask,
• wherein the LDD region is in contact with one end of a channel formation region, and one of the source and drain region is in contact with the other end of the channel formation region.

A method for manufacturing a semiconductor device comprising the steps of:

• forming a gate electrode over a substrate;
• forming a gate insulating film over the gate electrode and forming a semiconductor film over the gate insulating film without exposing to the atmosphere;
• forming an insulating film over the semiconductor film;
• crystallizing the semiconductor film by irradiating it with infrared light or ultraviolet light through the insulating film to form a crystalline semiconductor film;
• and
• forming a first mask over the insulating film;
• introducing a first impurity element into the semiconductor film by using the first mask;
• forming a second mask so as to cover a first part of the first mask, and in contact with a part of the insulating film and the first part of the first mask to expose a second part of the first mask;
• introducing a second impurity element into the semiconductor film by using the second mask to form an LDD region and a source or drain region;
• and
• forming an interlayer insulating film over the first mask, and in contact with the second part of the first mask, the second mask, and the insulating film,
• wherein the LDD region is in contact with one end of a channel formation region, and one of the source and drain region is in contact with the other end of the channel formation region.