CMP Polishing Method with Gas Cooling and Variable Load
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Solution Overview
Problem
Current semiconductor manufacturing processes face challenges in reducing surface defects such as corrosion and residual metal during chemical mechanical polishing (CMP), which affect yield and productivity.
Innovation Solution
A method involving a two-stage polishing process with varying loads and gas spraying to prevent corrosion, where a first load is applied for primary polishing, followed by a second, heavier load with gas application to remove remaining metal layers, and a touch-up polishing with a different slurry to ensure complete removal and improve foundation followability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single polishing process is used, then the manufacturing process is simple, but surface defects such as corrosion and residual metal remain
Solution Approach 1:
The polishing process is divided into two distinct stages: a first polishing process with a first load and a second polishing process with a second load greater than the first load. This segmentation allows each stage to address specific aspects of surface quality, effectively reducing corrosion and residual metal defects while maintaining process manageability.
Solution Approach 2:
The polishing load is dynamically adjusted between two stages. The first polishing process uses a lighter first load to perform initial polishing, while the second polishing process increases to a heavier second load to specifically target and remove residual metal and corrosion defects, optimizing surface quality at each stage.
2Reliability
If polishing time is extended to reduce surface defects, then surface quality improves, but productivity decreases
Solution Approach 1:
By segmenting the polishing process into two targeted stages with different loads, the method efficiently addresses surface defects without requiring excessive polishing time. The second polishing process with greater load specifically removes residual defects, achieving high surface quality while maintaining reasonable process duration for productivity.
Solution Approach 2:
The polishing load parameter is changed between two stages, with the second load being greater than the first load. This parameter change enables the second stage to rapidly remove residual metal and corrosion, improving surface quality efficiency and reducing total polishing time compared to using a single prolonged polishing process.
3Reliability
If a heavier load is applied throughout polishing, then residual metal is removed effectively, but corrosion increases
Solution Approach 1:
The process segments polishing into two stages: the first polishing process uses a lighter first load that minimizes corrosion generation, while the second polishing process uses a heavier second load applied after the first stage to effectively remove residual metal without generating excessive corrosion, since the critical period has already passed.
Solution Approach 2:
The first polishing process performs preliminary polishing with a lighter load before the second polishing process. This preliminary action prepares the surface and reduces the risk of corrosion that would occur if a heavy load were applied from the beginning, while still allowing effective residual metal removal in the subsequent second stage.
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 effectively reduces surface defects, improves yield by preventing short-circuiting, and shortens polishing time, while maintaining high clarity of the metal residue and flatness, thus enhancing manufacturing productivity.
Implementation Method 1
a gas nozzle 27, and the metal layer is polished while spraying a gas 33 onto the polishing surface 7a of the polishing pad 7
Implementation Method 2
A chemical mechanical polishing (CMP) for flattening a wafer surface is used in a manufacturing processes of a semiconductor device
Data Source
AI summary
According to an embodiment, a method of manufacturing a semiconductor device includes forming a wiring groove on an insulating film; forming a barrier metal layer and a metal layer; polishing the metal layer by applying a first load on the metal layer; and subsequently polishing the metal layer while applying a second load larger than the first load on the metal layer and spraying a gas onto a polishing pad. The polishing pad is in contact with the metal layer. The barrier metal layer covers an upper surface of the insulating film and an inner surface of the wiring groove, and the metal layer fills an inside of the wiring groove and covers the barrier metal layer.