Wafer Developing Apparatus Radial Puddle Spreading
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Solution Overview
Problem
Current photolithographic developing methods for semiconductor wafers face challenges with excessive developer usage, spattering, and reduced throughput due to larger wafer sizes, where the stationary developing method wastes developer and decreases reactivity, and the rotary method risks liquid spattering and non-uniform concentration.
Innovation Solution
A developing method involving a substrate holder that rotates a wafer while a developer nozzle forms a liquid puddle and spreads it radially, using a contact part with a smaller surface than the substrate to inhibit excessive developer use and spattering, and stir the developer with a turning flow to maintain concentration uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the stationary developing method is employed to process larger wafers, then the wafer size can be increased, but the amount of developer used increases and developer is wasted
Solution Approach 1:
The invention transitions from a stationary developing method to a dynamic method where the substrate rotates during development. This rotation enables the developer to be supplied at a moving position along the radius, allowing the liquid film to flow and cover the entire wafer surface efficiently, reducing developer waste while accommodating larger wafer sizes
Solution Approach 2:
The nozzle position is preliminarily configured to supply developer at a specific radial position on the rotating substrate. This preliminary positioning allows the developer to be deposited where it can most effectively spread across the wafer surface through centrifugal action, optimizing developer utilization
2Device complexity
If the stationary developing method is employed, then the developing process is simple, but the reaction time increases and throughput decreases
Solution Approach 1:
By introducing substrate rotation and moving the developer supply position along the radius, the developing process becomes dynamic. This creates continuous flow and renewal of developer contact with the resist pattern, significantly reducing reaction time and increasing throughput, while the added complexity remains manageable through coordinated rotation and positioning
3Area of stationary object
If the rotary developing method is employed to process larger wafers, then the wafer size can be increased, but the risk of liquid spattering increases
Solution Approach 1:
The invention applies different operational characteristics to different regions: the developer is supplied at a specific radial position where centrifugal forces are optimized, and the liquid film flows in a controlled manner from the supply position outward. This localized control of liquid flow dynamics prevents spattering while still enabling complete wafer coverage
Solution Approach 2:
The moving liquid film acts as an intermediary that transports developer from the supply position across the wafer surface. This controlled liquid film formation and flow mechanism prevents uncontrolled spattering while ensuring uniform developer distribution across the entire wafer
4Area of stationary object
If the rotary developing method is employed, then the developer can be distributed more uniformly, but the concentration uniformity may be compromised due to liquid flow
Solution Approach 1:
The continuous rotation and moving supply position create a dynamic equilibrium where developer is constantly replenished and distributed. The liquid film flows in a controlled manner that maintains relatively uniform concentration across the wafer surface, balancing distribution uniformity with concentration consistency
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 method reduces developer consumption, prevents spattering, and enhances throughput by maintaining uniform developer concentration and reaction efficiency across the wafer surface.
Implementation Method 1
a liquid film of the developer is formed on the substrate by the movement of the supply position of the developer and a centrifugal action
Implementation Method 2
the developer forming the liquid film flows
Implementation Method 3
bringing, simultaneously with the spreading of the liquid puddle on the whole surface of the substrate, a contact part into contact with the liquid puddle
Implementation Method 4
stir the developer with a turning flow to maintain concentration uniformity
Data Source
AI summary
A developing apparatus including a horizontal substrate holder, a rotating mechanism to rotate the substrate holder, a developer nozzle to supply a developer onto a part of the substrate to form a liquid puddle, a moving mechanism to move the developer nozzle in a radial direction of the rotating substrate, a contact part that moves with the developer nozzle and has a surface opposed to the substrate, which is smaller than the surface of the substrate, and a control unit to output a control signal such that a supply position of the developer on the substrate is moved in the radial direction of the substrate so that the liquid puddle is spread out on a whole surface of the substrate while the contact part is in contact with the liquid puddle.