Face-Up Wafer Electrochemical Planarization to Prevent Metal Dishing
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Solution Overview
Problem
Conventional chemical mechanical polishing (CMP) methods face challenges in uniformly polishing substrates, leading to non-uniform film thickness and dishing of metal materials, which can result in lithography issues and reduced die yield.
Innovation Solution
The use of electrochemical planarization apparatuses that include a chuck body, a spindle, and a conductive end effector to apply an electric current to an electrolyte, allowing for selective removal of metallic materials while preventing the removal of non-metallic materials, thereby achieving uniform film thickness across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CMP methods are used to planarize substrates, then material removal is achieved, but film thickness uniformity deteriorates due to non-uniform polishing rates across different materials
Solution Approach 1:
The patent replaces the conventional mechanical CMP system with an electrochemical planarization system. Instead of using mechanical abrasion through polishing pads and slurry, the invention uses electrochemical reactions where a conductive end effector applies electrical current to selectively remove metallic materials through controlled electrochemical dissolution, eliminating the mechanical forces that cause non-uniform polishing
Solution Approach 2:
The invention changes the fundamental parameter of material removal from mechanical force-based to electricity-based. By controlling electrical current density, voltage, and electrochemical reaction conditions, the system achieves selective and uniform removal of metallic materials without the mechanical pressure variations that cause dishing and non-uniformity in conventional CMP
2Manufacturing precision
If mechanical force is applied during CMP operations, then material removal is achieved, but selective removal uniformity deteriorates with faster removal of metal materials compared to dielectric materials
Solution Approach 1:
The patent eliminates mechanical force application by replacing the CMP mechanical system with an electrochemical system. The conductive end effector applies electrical current directly to the substrate surface, enabling selective removal of metallic materials through electrochemical reactions without mechanical contact, thereby preventing dishing and achieving uniform selective removal
Solution Approach 2:
The invention introduces an electrolyte as an intermediary medium between the conductive end effector and the substrate. The electrolyte facilitates electrochemical reactions at the substrate surface, enabling controlled and uniform material removal through ionic conduction and electrochemical dissolution rather than direct mechanical contact
3Manufacturing precision
If conventional CMP apparatuses are used, then substrate planarization is achieved, but material waste increases due to non-selective removal
Solution Approach 1:
The patent replaces mechanical abrasion with electrochemical dissolution, enabling highly selective removal of metallic materials. The electrochemical reactions occur only at conductive metal regions where electrical current is applied, preventing non-selective removal of dielectric materials and minimizing material waste while achieving planarization
Solution Approach 2:
The invention applies local quality by making the end effector conductive and applying electrical current only to specific regions where metallic materials need removal. The electrochemical planarization process selectively acts on conductive regions while leaving non-conductive dielectric materials intact, achieving precise local material removal without waste
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 enhances film thickness uniformity and prevents dishing, leading to improved die yield and reduced mechanical wear, allowing for more precise and uniform planarization of substrates.
Implementation Method 1
a current source configured to provide an electric current to an electrolyte within an open interior defined by the retaining wall
Data Source
AI summary
Exemplary substrate electrochemical planarization apparatuses may include a chuck body defining a substrate support surface. The apparatuses may include a retaining wall extending from the chuck body. The apparatuses may include an electrolyte delivery port disposed radially inward of the retaining wall. The apparatuses may include a spindle that is positionable over the chuck body. The apparatuses may include an end effector coupled with a lower end of the spindle. The end effector may be conductive. The apparatuses may include an electric contact extending from the chuck body or retaining wall. The apparatuses may include a current source. The current source may be configured to provide an electric current to an electrolyte within an open interior defined by the retaining wall.