Wafer Elevation for Anti-Reflective Layer Removal
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Solution Overview
Problem
Conventional techniques for removing photolithographic films, such as anti-reflective coatings, are inefficient as they often leave residual layers due to the densification caused by high temperature baking during dry ashing processes, which complicates subsequent wet etching.
Innovation Solution
Elevating the wafer away from the substrate support member reduces thermal heating, keeping the wafer temperature below the bake-in temperature of the anti-reflective layer, thereby avoiding densification and allowing for complete removal of the anti-reflective layer without substantial modifications to conventional equipment or processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the wafer temperature is kept below the bake-in temperature of the anti-reflective layer, then densification is avoided, but photoresist removal efficiency decreases
Solution Approach 1:
The patent applies preliminary action by using the elevated pins to position the wafer in a protected state before the anti-reflective layer processing begins. This pre-positioning ensures that when high temperature is applied for photoresist removal, the anti-reflective layer is already shielded from thermal densification, allowing optimal conditions for both removal efficiency and layer integrity
Solution Approach 2:
The retractable pins serve as an intermediary mechanism between the hot substrate support member and the wafer. They transfer the mechanical support function while controlling thermal exposure, acting as a mediator that allows high chamber temperature for efficient photoresist removal while preventing excessive heat transfer to the wafer that would cause anti-reflective layer densification
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 enables the removal of at least 98% of the anti-reflective layer, improving the efficiency and completeness of the process compared to conventional methods, as demonstrated by experiments showing complete removal of DUO layers.
Implementation Method 1
thermal heating from the substrate support member to the wafer
Implementation Method 2
The dry ash process includes a wafer temperature of greater than 250 degrees Celsius in an oxygen atmosphere
Data Source
AI summary
Techniques for removal of photolithographic films used in the manufacture of semiconductor devices are provided. A substrate support member of a first processing chamber includes at least three retractable pins capable of elevating a wafer from a surface of the substrate support member. In addition, the first processing chamber is configured to automatically maintain the substrate support member at a first temperature. The wafer is elevated from the surface of the substrate support member using the at least three retractable pins. Thermal heating of the substrate from the substrate support member is reduced. A photoresist layer of the substrate is etched away while the substrate is in an elevated position. An anti-reflective layer of the substrate can be etched to remove substantially all of the anti-reflective layer. In a specific embodiment, the anti-reflective layer includes a DUO™ Bottom Anti-Reflective Coating by Honeywell International Inc.