Fluoropolymer mask for transistor channel definition

A method for controlling the channel length in a thin-film transistor (TFT), the method comprising:

• providing a substrate with a top surface;
• forming a printed ink first source/drain (S/D) structure with a first edge overlying the substrate top surface;
• inkjet printing a fluoropolymer mask to cover the first S/D structure;
• forming a boundary region, between a first edge of the fluoropolymer mask and the first edge of the printed ink first S/D structure, having a width;
• printing a primary ink at least partially overlying the boundary region;
• forming a printed ink second S/D structure on the substrate top surface, having a first edge adjacent to the fluoropolymer mask first edge;
• removing the fluoropolymer mask;
• leaving the printed ink first S/D structure first edge separated from the printed ink second S/D structure first edge by a space equal to the boundary region width;
• and,
• forming a semiconductor channel partially overlying the printed ink first S/D structure and the printed ink second S/D structure, having a channel length equal to the boundary region width.

A method for controlling the separation between printed ink structures, the method comprising:

• providing a substrate with a top surface;
• forming a first structure with a first edge overlying the substrate top surface;
• depositing a fluoropolymer mask to cover the first structure using a printer deposition process with a printer tolerance error of X;
• forming a boundary region, between a first edge of the fluoropolymer mask and the first edge of the first structure, having a width equal to X plus a thickness of the fluoropolymer mask;
• printing a primary ink at least partially overlying the boundary region;
• and,
• forming a printed ink second structure having a first edge adjacent to the fluoropolymer mask first edge.

A method for controlling the channel length in a thin-film transistor (TFT), the method comprising:

• providing a substrate with a top surface;
• forming a printed ink first source/drain (S/D) structure with a first edge overlying the substrate top surface;
• depositing a fluoropolymer mask to cover the first S/D structure using a printer deposition process with a printer tolerance error of X;
• forming a boundary region, between a first edge of the fluoropolymer mask and the first edge of the printed ink first S/D structure, having a width equal to X plus a thickness of the fluoropolymer mask;
• printing a primary ink at least partially overlying the boundary region;
• forming a printed ink second S/D structure on the substrate top surface, having a first edge adjacent to the fluoropolymer mask first edge;
• removing the fluoropolymer mask;
• leaving the printed ink first S/D structure first edge separated from the printed ink second S/D structure first edge by a space equal to the boundary region width;
• and,
• forming a semiconductor channel partially overlying the printed ink first S/D structure and the printed ink second S/D structure, having a channel length equal to the boundary region width.