Resist Underlayer Film Composition for Semiconductor Patterning
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Solution Overview
Problem
Current resist underlayer film compositions for semiconductor manufacturing lack sufficient resistance to basic hydrogen peroxide aqueous solutions, adequate gap-filling, and planarization characteristics, particularly in advanced processes with irregular surfaces or steps, and often suffer from insufficient dry etching resistance.
Innovation Solution
A resist underlayer film composition comprising a polymer with specific repeating units, a polyphenol compound, and an organic solvent, which forms a film with enhanced adhesion to silicon substrates and structural substrates, providing improved resistance to basic hydrogen peroxide, excellent gap-filling, and planarization capabilities, along with controlled etching characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a photoresist film with sufficient thickness is used to ensure pattern formation, then the pattern can be formed with adequate aspect ratio, but the resolution decreases when pattern width is narrowed without changing film thickness
Solution Approach 1:
The patent divides the single photoresist film into two separate layers: an upper photoresist film for pattern formation and a lower resist underlayer film for etching resistance. This segmentation allows each layer to be optimized independently - the upper layer can be thin for high resolution while the lower layer provides sufficient thickness for etching protection, resolving the contradiction between resolution and pattern formation capability.
2Manufacturing precision
If the photoresist film thickness is reduced to maintain resolution, then the aspect ratio becomes manageable, but the film becomes too thin to serve as an effective etching mask
Solution Approach 1:
By segmenting the etching mask function into a separate lower resist underlayer film, the upper photoresist film can be kept thin for high resolution while the lower film provides the necessary etching resistance. The lower film is specifically designed with materials having high etching selectivity difference relative to the substrate.
Solution Approach 2:
The lower resist underlayer film acts as an intermediary between the upper photoresist film and the substrate. It receives the pattern from the upper film and transfers it to the substrate through etching, while providing the necessary mechanical support and etching resistance that a thin upper film cannot provide alone.
3Manufacturing precision
If a resin with smaller light absorbance is selected to increase resolution at shorter wavelengths, then the resolution improves, but the dry etching rate increases reducing etching resistance
Solution Approach 1:
The patent segments the functional requirements into two different resin systems: the upper photoresist film uses resins optimized for lithographic performance (novolak, polyhydroxystyrene, or aliphatic polycyclic skeletons with appropriate absorbance), while the lower resist underlayer film uses resins optimized for etching resistance (polyglycidyl methacrylate, polyhydroxypropyl methacrylate, or their copolymers). This allows each layer to have optimal properties for its specific function.
Solution Approach 2:
Different regions of the resist structure are given different material qualities - the upper layer has material properties optimized for light interaction and pattern formation, while the lower layer has material properties optimized for chemical resistance and etching stability. This local differentiation resolves the contradiction between optical performance and etching performance.
4Adaptability or versatility
If conventional resist underlayer film compositions are used, then the multilayer resist method can be implemented, but the resistance to basic hydrogen peroxide aqueous solution, gap-filling, and planarization characteristics are insufficient
Solution Approach 1:
The patent specifies precise compositional parameters for the lower resist underlayer film: it must contain polyglycidyl methacrylate, polyhydroxypropyl methacrylate, or their copolymers with controlled molecular weights and compositions. These parameter specifications ensure adequate resistance to basic hydrogen peroxide aqueous solutions while maintaining gap-filling and planarization capabilities.
Solution Approach 2:
The lower resist underlayer film uses composite polymer systems combining polyglycidyl methacrylate and polyhydroxypropyl methacrylate in specific ratios, creating a material with enhanced chemical resistance, adhesion, and planarization properties compared to conventional single-polymer underlayer films.
Data Source
Figure 1(A)~1(F)
Figure 2(G)~3(K)
AI summary
PROVIDED IS A RESIST UNDERLAYER FILM COMPOSITION WHICH IS EXCELLENT IN RESISTANCE TO A BASIC HYDROGEN PEROXIDE AQUEOUS SOLUTION, IN GAP-FILLING AND PLANARIZATION CHARACTERISTICS, AND IN DRY ETCHING CHARACTERISTIC, WHEREIN THE RESIST UNDERLAYER FILM COMPOSITION IS USED FOR A MULTILAYER RESIST METHOD, COMPRISING: (A1) A POLYMER (1A) COMPRISING ONE, OR TWO OR MORE, OF A REPEATING UNIT REPRESENTED BY FOLLOWING GENERAL FORMULA (1); (A2) ONE, OR TWO OR MORE, OF A POLYPHENOL COMPOUND HAVING A FORMULA WEIGHT OF 2,000 OR LESS AND NOT HAVING A 3,4-DIHYDROXY PHENYL GROUP; AND (B) AN ORGANIC SOLVENT.