Electroless Plating Void Prevention via Dynamic Temperature Control
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Solution Overview
Problem
In electroless plating, forming a void in recesses on substrates is a challenge due to uneven metal precipitation, as the plating metal may fill the opening portions before the bottom or central portions, leading to incomplete filling and void formation.
Innovation Solution
A substrate liquid processing method involving multi-step temperature control of the electroless plating liquid, where the temperature is initially raised for active precipitation and then lowered to inhibit reaction in the opening portions, allowing continuous precipitation from the bottom and central portions, preventing void formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the temperature of the electroless plating liquid is raised to accelerate metal precipitation, then the plating speed is improved, but metal precipitates unevenly filling opening portions before bottom portions causing void formation
Solution Approach 1:
The patent applies dynamic temperature control by changing the temperature of the electroless plating liquid during the plating process. The temperature is raised to a first temperature to accelerate metal precipitation and improve plating speed, then lowered to a second temperature to suppress precipitation and enable uniform filling from bottom to opening portions, preventing void formation. This dynamic adjustment resolves the contradiction between plating speed and filling uniformity.
Solution Approach 2:
The patent employs periodic temperature adjustment with distinct phases: a first period at elevated temperature for rapid metal precipitation, followed by a second period at lowered temperature for controlled filling. This periodic action allows the system to achieve both high productivity during the first period and manufacturing precision during the second period, resolving the technical contradiction.
2Productivity
If the temperature is kept high for rapid plating, then productivity is improved, but voids form due to preferential filling of opening portions
Solution Approach 1:
The patent uses dynamic temperature adjustment where the temperature is first raised to accelerate plating rate for high productivity, then lowered to suppress precipitation in opening portions and promote bottom-up filling for reliable void-free results. This dynamic control sequence ensures both productivity and reliability are achieved.
Solution Approach 2:
The patent applies preliminary anti-action by lowering the temperature after initial plating to prevent the harmful effect of void formation. The temperature reduction counteracts the tendency for metal to preferentially fill opening portions, ensuring reliable void-free filling while maintaining high overall productivity from the initial high-temperature phase.
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 ensures complete filling of the recess with metal without forming voids, effectively burying the metal in the substrate recesses.
Implementation Method 1
capable of rapidly increasing a temperature of the plating liquid on a substrate by covering the substrate with a cover having a heater
Implementation Method 2
adjusting a temperature of the liquid film from a first temperature at which a metal is precipitated on the seed layer to a second temperature lower than the first temperature
Data Source
AI summary
A substrate liquid processing method includes preparing a substrate having a surface including a recess on which a seed layer is stacked; supplying an electroless plating liquid onto the surface of the substrate to fill the recess with the electroless plating liquid while forming a liquid film of the electroless plating liquid on the surface; and adjusting a temperature of the liquid film from a first temperature at which a metal is precipitated on the seed layer to a second temperature lower than the first temperature to fill the recess with the metal starting from a bottom portion of the recess such that a void is not formed therein.