Adjustable Anode Mask for Plating Uniformity
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Solution Overview
Problem
The terminal effect in electrolytic plating processes for semiconductor wafers leads to reduced in-plane uniformity of film thickness due to varying seed layer thickness, resist aperture ratios, and plating solution resistances, requiring adjustments in electric fields for each substrate, which is time-consuming and inefficient with existing anode regulation plates.
Innovation Solution
A plating apparatus with an anode mask and regulation plate that allows adjustable openings to concentrate the electric field on the substrate's central portion, using a mechanism with aperture blades for the anode mask and an elastic body for the regulation plate to adjust opening diameters, enabling tailored adjustments for substrates with different characteristics and processing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an anode regulation plate is used to adjust electric field distribution, then in-plane uniformity of film thickness is improved, but device complexity increases and processing efficiency decreases due to need for multiple plates
Solution Approach 1:
The patent applies universality by designing a single anode regulation plate with multiple openings of different diameters that can be selectively used for different substrate types. Instead of requiring multiple separate regulation plates for different plating conditions, one multi-functional plate with variable opening configurations addresses various substrate characteristics (thin seed layers, low resist aperture ratios) through selective opening selection, thereby reducing device complexity while maintaining manufacturing precision.
Solution Approach 2:
The patent applies dynamics by making the anode regulation plate's opening configuration changeable during operation. The plate includes openings with different diameters that can be selectively opened or closed based on the substrate being processed. This dynamic reconfiguration allows the system to adapt to different plating conditions (varying seed layer thicknesses, resist aperture ratios) without requiring physical plate changes, thus improving processing efficiency while maintaining film thickness uniformity.
2Manufacturing precision
If multiple anode regulation plates are prepared for different substrates, then manufacturing precision is maintained, but productivity decreases due to plate replacement time
Solution Approach 1:
The patent applies universality by designing a single anode regulation plate with multiple openings of different diameters that can be selectively used for different substrate types. Instead of requiring multiple separate regulation plates for different plating conditions, one multi-functional plate with variable opening configurations addresses various substrate characteristics (thin seed layers, low resist aperture ratios) through selective opening selection, thereby reducing device complexity while maintaining manufacturing precision.
Solution Approach 2:
The patent applies dynamics by making the anode regulation plate's opening configuration changeable during operation. The plate includes openings with different diameters that can be selectively opened or closed based on the substrate being processed. This dynamic reconfiguration allows the system to adapt to different plating conditions (varying seed layer thicknesses, resist aperture ratios) without requiring physical plate changes, thus improving processing efficiency while maintaining film thickness uniformity.
3Manufacturing precision
If opening diameter is increased to reduce terminal effect, then in-plane uniformity improves, but electric current concentration in central portion decreases
Solution Approach 1:
The patent applies dynamics by making the anode regulation plate's opening configuration changeable during operation. The plate includes openings with different diameters that can be selectively opened or closed based on the substrate being processed. This dynamic reconfiguration allows the system to adapt to different plating conditions (varying seed layer thicknesses, resist aperture ratios) without requiring physical plate changes, thus improving processing efficiency while maintaining film thickness uniformity.
Solution Approach 2:
The patent applies local quality by providing different opening diameters in the anode regulation plate to address different regional requirements on the substrate. For substrates with thin seed layers or low resist aperture ratios where terminal effect is prominent, larger openings are selected to increase electric field penetration to the central portion. For substrates where uniform current distribution is sufficient, smaller openings can be used. This localized approach to electric field control optimizes both in-plane uniformity and central portion plating rate for different substrate conditions.
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 curbs the reduction in in-plane uniformity by concentrating the electric field on the central portion of substrates with thinner seed layers or lower resist aperture ratios, improving film thickness uniformity without the need for multiple anode regulation plates, thus enhancing processing efficiency.
Implementation Method 1
A plating apparatus with an anode mask and regulation plate that allows adjustable openings to concentrate the electric field on the substrate's central portion
Implementation Method 2
an electric current corresponding to combined resistance of an electrical resistance value of the plating solution and electrical resistance value of the seed layer between a central portion of the substrate and the electrical contact flows through the central portion of the substrate
Implementation Method 3
When wiring or bumps are formed by the electrolytic plating process, a seed layer (feeder layer) with low electrical resistance is formed on surfaces of barrier metal provided in the wiring grooves, holes, or resist openings in the substrates. A plating film grows on a surface of the seed layer.
Data Source
AI summary
A plating apparatus according to the present disclosure includes an anode holder configured to hold an anode; a substrate holder placed opposite the anode holder and configured to hold a substrate; and an anode mask installed on a front face of the anode holder and provided with a first opening adapted to allow passage of an electric current flowing between an anode and the substrate. The diameter of the first opening in the anode mask is configured to be adjustable. When a first substrate is plated, a diameter of the first opening is adjusted to a first diameter. When a second substrate is plated, the diameter of the first opening is adjusted to a second diameter smaller than the first diameter.