Method of forming ESD protection device with thick poly film
View Patent ↗An ESD protection device with thicker polysilicon film, an electronic apparatus having the same, and a method for manufacturing the same are provided. The ESD protection device can be a diode or a MOS transistor with a thicker polysilicon film employed in an ESD protection circuit to protect an electronic apparatus. The electronic apparatus includes a substrate having a device area and an ESD protection circuit area. A first polysilicon film of a first thickness is formed on the device area of the substrate, so as to form an electronic device. A second polysilicon film of a second thickness is formed on the ESD protection circuit area, so as to form an ESD protection device. The second thickness, which is preferably about in the range of 100 to 500 nanometers, is thicker than the first thickness.
1. A method for forming an ESD protection device in an ESD protection circuit, comprising:
providing a substrate having a device area and an ESD protection circuit area;
forming a first polysilicon film of a first thickness on said substrate to cover said device area and said ESD protection circuit area;
forming a patterned photoresist layer on said first polysilicon film to expose a portion of said first polysilicon film corresponding to said device area;
etching said first polysilicon film to expose said substrate by using said patterned photoresist layer as a mask;
removing said patterned photoresist layer; and
depositing a second polysilicon film of a second thickness on said substrate so as to form a polysilicon film on said device area having the second thickness and a polysilicon film on said ESD protection circuit area having a third thickness, wherein said third thickness equals said first thickness plus said second thickness.
2. The method according to claim 1 , further comprising forming first source/drain regions separated by a first channel in said polysilicon film on said device area.
3. The method according to claim 2 , further comprising forming second source/drain regions separated by a second channel in said polysilicon film on said ESD protection circuit area.
4. The method according to claim 1 , further comprising forming an n-type doped region and a p-type doped region in said polysilicon film to form a PN diode on said ESD protection circuit area.
5. The method according to claim 4 , further comprising forming an intrinsic region between said n-type doped region and said p-type doped region in said third polysilicon film to form a PIN diode.
6. The method according to claim 1 , wherein said third thickness is in a range of about 100 to 500 nanometers.