Second Resist Film Additives for Double Patterning Acid Compensation
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Solution Overview
Problem
The double patterning technique in semiconductor manufacturing faces issues with pattern errors due to the roughened surface of the first hardmask pattern, leading to unsatisfactory pattern formation, such as wobbling edges and dimensional variations, caused by acid entrapment in the cavities of the roughened surface during the second resist exposure.
Innovation Solution
The second resist film contains a higher amount of additives that improve sensitivity and alkaline solubility compared to the first resist film, including a greater amount of photoacid generators or 2-nitrobenzyl ether, to compensate for acid deficiency and ensure effective development, thereby preventing pattern errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If double patterning is used to improve resolution, then pattern contrast is improved, but pattern errors occur due to acid entrapment in roughened surface cavities
Solution Approach 1:
The patent changes the chemical composition parameters of the resist film by incorporating specific additives (basic compounds like quaternary ammonium hydroxides, phosphine oxides, or carboxylic acid derivatives) to alter the development characteristics and compensate for acid entrapment effects, thereby resolving the pattern formation accuracy issue while maintaining the resolution benefits of double patterning
2Device complexity
If the second resist film uses the same composition as the first, then process simplicity is maintained, but sensitivity and alkaline solubility deficiencies occur due to roughened surface
Solution Approach 1:
The patent applies different compositional qualities to different stages of the patterning process by using a first resist film with standard composition for the first exposure, and a second resist film with enhanced additives specifically for the second exposure on the roughened surface, optimizing each stage for its specific requirements
3Manufacturing precision
If photoacid generator amount is increased in the second resist film, then sensitivity is improved, but cost and potential over-exposure increase
Solution Approach 1:
The patent optimizes the photoacid generator concentration within a specific range (0.01-10 wt%, preferably 0.05-5 wt%) to achieve sufficient sensitivity improvement without excessive concentration that would cause over-exposure or cost issues, demonstrating precise parameter control
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively prevents pattern errors and achieves finer, desirable pattern formation by compensating for the sensitivity and alkaline solubility deficiencies in the second resist film, even when exposed to a roughened surface, resulting in improved resolution and shape accuracy.
Implementation Method 1
at least one of an additive which improves sensitivity of the resist and an additive which improves alkaline solubility of exposed part of the resist is contained in a greater amount in the second resist film than in the first resist film
Implementation Method 2
at least one of an additive which improves sensitivity of the resist and an additive which improves alkaline solubility of exposed part of the resist is contained in a greater amount in the second resist film than in the first resist film
Data Source
AI summary
After formation of an underlayer film and an intermediate layer film, a resist pattern formed by the first pattern exposure with the first resist film and the second pattern exposure with the second resist film is transferred to the intermediate layer film. The underlayer film is etched using an intermediate layer pattern as a mask to form an underlayer film pattern. Herein, the first and second resist films are chemically amplified resist films. The second resist film contains a greater amount of additive which improves the sensitivity of the resist or which improves the alkaline solubility of resist exposed part.