Common Fill Process for Metal Gates and Contacts
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Solution Overview
Problem
The 'gate-last' technique in semiconductor processing involves multiple deposition and chemical mechanical polishing (CMP) steps, which can lead to defects such as microscratches and slurry defects, reducing product yields and limiting material flexibility for gate electrodes.
Innovation Solution
A method is introduced for forming gate electrode structures and conductive contacts using a common fill process, involving the formation of a sacrificial gate electrode material, followed by the removal of this material to define openings, and subsequent filling with a conductive fill material, allowing for planarization to remove excess material outside the openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple deposition and CMP steps are used in gate-last technique, then gate electrode material flexibility is improved, but manufacturing defects increase and product yields decrease
Solution Approach 1:
The patent combines the formation of gate electrode and contact hole fill into a single deposition step. By forming both structures simultaneously from the same conductive material layer, the process eliminates multiple deposition and CMP steps while maintaining material flexibility. This merging approach directly reduces manufacturing defects and improves product yields while preserving the ability to use various gate electrode materials.
Solution Approach 2:
The conductive material layer serves multiple functions simultaneously: it forms both the gate electrode structure and the contact hole fill. This multi-functional approach allows a single deposition process to accomplish what previously required multiple specialized steps, thereby reducing complexity and defect formation while maintaining versatility in material selection for gate electrodes.
2Ease of manufacture
If multiple deposition and CMP steps are performed, then gate electrode structure is formed, but manufacturing complexity and process time increase
Solution Approach 1:
The patent merges multiple process steps (deposition for gate electrode, deposition for contact fill, and associated CMP steps) into a single deposition operation. This consolidation simplifies the manufacturing process by reducing the total number of steps required to form both gate electrode and contact structures, thereby improving ease of manufacture and reducing process complexity.
Solution Approach 2:
The conductive material layer is deposited in advance to simultaneously form both gate electrode and contact hole fill structures before final patterning steps. This preliminary action allows subsequent processing to work with pre-formed structures, eliminating the need for multiple later deposition and CMP steps and simplifying the overall manufacturing sequence.
3Manufacturing precision
If CMP steps are used to remove excess material, then gate electrode and contact structures are defined, but manufacturing defects such as microscratches and slurry defects increase
Solution Approach 1:
The patent extracts the harmful CMP step from the process sequence by using selective removal techniques instead. Excess conductive material is removed through selective etching or dissolution processes that target specific areas without requiring mechanical polishing. This extraction of the CMP step eliminates the source of microscratches and slurry defects while still achieving precise structure definition.
Solution Approach 2:
The patent uses a sacrificial material or temporary structure that is easily removable without CMP. The excess conductive material is designed to be selectively removed through simple chemical or physical means, replacing the need for damaging mechanical polishing. This approach uses disposable or temporary elements that facilitate defect-free structure definition.
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 reduces defects and increases material flexibility for gate electrodes, improving product yields and performance by simplifying the process and minimizing CMP-related issues.
Implementation Method 1
performing a deposition process to fill the conductive contact opening and the gate electrode opening with a conductive fill material
Implementation Method 2
performing a deposition process to fill the conductive contact opening and the gate electrode opening with a conductive fill material
Data Source
AI summary
The method described herein involves a method of forming metal gates and metal contacts in a common fill process. The method may involve forming a gate structure comprising a sacrificial gate electrode material, forming at least one conductive contact opening in a layer of insulating material positioned adjacent the gate structure, removing the sacrificial gate electrode material to thereby define a gate electrode opening, and performing a common deposition process to fill the conductive contact opening and the gate electrode opening with a conductive fill material.