Hard Fill Material Restricts Conductive Smearing During Polishing
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Solution Overview
Problem
Conductive materials like platinum and platinum alloys often become embedded in nonconductive materials during chemical-mechanical polishing (CMP) of microelectronic substrates, leading to short circuits and defects due to smearing, which existing techniques fail to adequately address.
Innovation Solution
The use of a hard fill material such as titanium nitride (TiN) with a hardness of at least 30 GPa, deposited using low-temperature CVD, restricts the movement of conductive materials during polishing, preventing smearing by compressing and restricting the conductive material's spread into apertures, and allowing for effective removal with a single CMP or ECMP procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP process is used to remove conductive material, then polishing effectiveness is improved, but conductive material becomes embedded in nonconductive material causing defects
Solution Approach 1:
The patent changes the physical and chemical parameters of the polishing slurry, including pH value, oxidation-reduction potential, temperature, and composition ratios of oxidizing agents and chelating agents, to optimize the selective removal of conductive material while preventing embedding in nonconductive material
Solution Approach 2:
The patent introduces a specially formulated polishing slurry containing oxidizing agents, chelating agents, and abrasive particles as an intermediary medium that facilitates selective chemical-mechanical removal of conductive material while protecting nonconductive material from embedding defects
2Manufacturing precision
If multiple polishing procedures are used to remove embedded conductive material, then manufacturing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies preliminary protective measures during the polishing process by formulating a slurry that prevents conductive material embedding before it occurs, and includes in-situ regeneration capabilities that maintain optimal polishing conditions throughout the process, eliminating the need for multiple sequential polishing procedures
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 significantly reduces conductive material smearing and eliminates the need for additional dry etch procedures, enhancing the effectiveness of polishing and reducing manufacturing costs by ensuring precise removal of conductive materials without embedding them in the fill material.
Implementation Method 1
The use of a hard fill material such as titanium nitride (TiN) with a hardness of at least 30 GPa, deposited using low-temperature CVD, restricts the movement of conductive materials during polishing, preventing smearing by compressing and restricting the conductive material's spread into apertures
Implementation Method 2
deposited using low-temperature CVD
Implementation Method 3
chemical-mechanical polishing (CMP)
Data Source
AI summary
Polishing systems and methods for removing conductive material (e.g., noble metals) from microelectronic substrates are disclosed herein. Several embodiments of the methods include forming an aperture in a substrate material, disposing a conductive material on the substrate material and in the aperture, and disposing a fill material on the conductive material. The fill material at least partially fills the aperture. The substrate material is then polished to remove at least a portion of the conductive material and the fill material external to the aperture during which the fill material substantially prevents the conductive material from smearing into the aperture during polishing the substrate material.