Wafer Developing Method with Dynamic Dispensing Speed
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Solution Overview
Problem
The increasing demand for higher integration of ICs in smaller electronic products poses challenges in the precise formation of desired patterns of multiple thin film layers on substrate wafers during the photolithography process, particularly in achieving uniformity and reducing defects in the developing process.
Innovation Solution
A method involving dynamic dispensing of developer and rinse solutions onto a rotating wafer at controlled speeds, with nozzles moving along specific paths to ensure uniform coverage and minimize splashback, followed by a higher speed rotation to dry the wafer, optimizing the spin coating process to enhance pattern uniformity and reduce defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wafer is rotated at high speed to spin dry the surface, then the excess solution is effectively removed, but the uniformity of solution distribution during dispensing is compromised
Solution Approach 1:
The patent applies dynamics by varying the rotation speed of the wafer during different stages of the dispensing process. The wafer is rotated at a first speed during dispensing to ensure uniform distribution, then accelerated to a second, higher speed to remove excess solution. This dynamic speed adjustment resolves the contradiction between achieving uniformity and removing excess material effectively.
Solution Approach 2:
The patent implements periodic action through multi-stage rotation speed changes. The wafer undergoes periodic acceleration between dispensing stages, with each stage having a specific rotation speed optimized for its function. This periodic speed modulation allows the system to achieve both uniform distribution and effective excess removal at different time intervals.
2Manufacturing precision
If the developer solution is dispensed onto a stationary or slowly rotating wafer, then uniform coverage is achieved, but excess solution cannot be effectively removed
Solution Approach 1:
The patent uses dynamic rotation speed control to resolve this contradiction. During the dispensing phase, the wafer rotates at a controlled first speed that ensures uniform solution distribution. After dispensing, the rotation speed is increased to a second, higher speed to effectively remove excess solution through centrifugal force. This dynamic transition addresses both requirements sequentially.
Solution Approach 2:
The patent applies preliminary action by first establishing uniform solution distribution at a moderate rotation speed before accelerating to remove excess solution. The initial dispensing phase at controlled speed prepares the uniform base layer, and only after this is achieved does the system increase speed for excess removal, ensuring both uniformity and reliability.
3Reliability
If the wafer rotation speed is increased to remove excess solution, then defect counts are reduced, but the dispensing uniformity is affected
Solution Approach 1:
The patent resolves this contradiction through dynamic speed control during dispensing. The wafer is rotated at an optimized first speed during the actual dispensing operation to ensure uniform solution distribution and pattern formation. After dispensing completes, the speed is increased to a second, higher value for excess solution removal. This temporal separation of speed regimes maintains both dispensing uniformity and defect reduction.
Solution Approach 2:
The patent implements periodic action by alternating between two distinct rotation speed regimes. The first regime (lower speed) operates during dispensing to ensure uniformity, while the second regime (higher speed) operates afterward for excess removal and defect reduction. This periodic switching between speed states allows the system to optimize for each function at the appropriate time.
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 improves pattern uniformity and significantly reduces defect counts by ensuring uniform solution distribution and effective removal of excess solution, enhancing the precision and reliability of IC fabrication.
Implementation Method 1
rotating a wafer at a first rotating speed, and then dispensing a developer solution onto the wafer at the first rotating speed
Implementation Method 2
pattern-exposed to lithographic equipment in order to transcribe a selected circuit pattern
Data Source
AI summary
A developing method is provided. The developing method includes rotating a wafer. The developing method also includes dispensing, through a first nozzle, a developer solution onto the rotated wafer through a first nozzle at a first rotating speed. The developing method further includes dispensing, through a second nozzle, a rinse solution onto the rotated wafer through a second nozzle at a second rotating speed. The second rotating speed is less than the first rotating speed. In addition, the developing method includes simultaneously moving the first nozzle and the second nozzle during either the dispensing of the developer solution or the dispensing of the rinse solution.