Lithography forms the backbone of a typical semiconductor device fabrication run. It enables us to ‘draw’/ ‘write’ micrometre or nanometre sized patterns, thereby defining the device dimensions.
In optical lithography, we ‘write’ using an ultraviolet (UV) beam, and pattern sizes can be as small as a few micrometres. Even smaller, nanometre-sized patterns can be written via e-beam lithography which uses a beam of electrons to ‘write’. In both cases, ‘writing’ is done on special light-sensitive (or electron-sensitive) materials known as resists. These are chemically processed after exposure (to light/ electron beam) to reveal the written pattern. Precise control over instrument, beam, chemicals and time is necessary to make any lithographic process a success.
IITBNF has multiple optical lithography tools with different pattern dimension limits. We also have a laser writer system that is capable of producing mask plates with micrometre-sized patterns for use in the optical lithography tools. The best resolution at IITBNF (< 20 nm) is achieved through our state-of-the-art e-beam lithography tool: Raith 150 Two. This tool can also be used for in-situ silicon dioxide and metal deposition using its electron beam induced deposition (EBID) feature. For both optical & e-beam tools, resist spinners dedicated to different types of resists are available with capabilities to process 2”, 4” & 8” wafers. All lithography tools are housed in separate clean rooms with tight control over temperature, humidity & lighting conditions.
Instrument | Location | Contamination category | |
---|---|---|---|
1 | Double Sided Aligner (DSA) | 20 | litho/analytical |
2 | RaithEBL_Short | 20 | litho/analytical |
3 | Karl Suss MJB3 Mask Aligner | 17 | litho/analytical |
4 | Laser Writer | 17 | litho/analytical |
5 | Spinner 2 inch (SU8, PPR) | 17 | litho/analytical |
6 | Spinner 2 inch (General Purpose) | 17 | litho/analytical |
7 | Spinner 8 inch (General Purpose) | 20 | litho/analytical |
8 | Spinner 2 inch (PPR) | 20 | litho/analytical |
9 | Spinner 4 inch (PMMA) | 20 | litho/analytical |
10 | Karl Suss MJB4 Mask Aligner | 17 | litho/analytical |
11 | Double Side Mask Aligner – Suss Microtech | 29 | litho/analytical |
12 | Spin Coater – Laurell | 29 | litho/analytical |
13 | RaithEBL_Long | 20 | litho/analytical |