How to Clean Tiny Chip Patterns Using a Special Chemical Developer

This patent describes a method for making advanced computer chips using extreme ultraviolet light and a special chemical developer that cleans away tiny metal leftover bits from the chip's patterns.

What it covers

This method improves how tiny patterns are made on computer chips, especially for advanced manufacturing using extreme ultraviolet (EUV) light. It starts by putting a special light-sensitive material, called a photoresist, onto a silicon wafer, where this photoresist contains metal. After exposing this photoresist to light to create a pattern, the process uses a unique chemical liquid, called a first developer, to wash away the unexposed parts. This first developer (Claim 1) is mostly an organic solvent (at least 60% by weight) and includes a chemical additive, specifically a base, designed to remove any tiny metal residuals that might be left behind from the metal-containing photoresist. After this cleaning and patterning, the remaining photoresist acts like a stencil for etching the underlying material layer.

What it doesn't cover

• —Does not cover lithography methods that use photoresists without a metal-containing chemical.
• —Does not cover developers where the organic solvent makes up less than 60% of the developer's total weight.
• —Does not cover developers that do not include a base as a chemical additive to remove metal residuals.
• —Does not cover processes where the etching of the material layer happens before the first developing step.
• —Does not cover a two-step developing process where the second developer also contains a chemical additive (Claim 7 specifies the second developer is 'free of additive').

The clever bit

The innovation lies in precisely formulating the developer chemical. By combining a high percentage of organic solvent with a specific chemical additive (a base), the developer effectively cleans away tiny metal bits left over from the photoresist, which is critical for making extremely small and accurate patterns on chips.

Why it matters

This patent is crucial for making the smallest, most powerful computer chips. As chips get smaller, the manufacturing process becomes incredibly precise, and even tiny leftover materials can cause defects. By effectively removing metal residuals during the patterning process, this invention helps ensure that advanced chips, like those made by TSMC, can achieve their intended performance and reliability.

Real-world examples

• 1.Advanced semiconductor manufacturing processes
• 2.EUV (Extreme Ultraviolet) lithography for microchip fabrication
• 3.Manufacturing of high-performance CPUs and GPUs
• 4.Production of memory chips (DRAM, NAND flash)
• 5.Fabrication of logic chips for smartphones and data centers