CMP Pad Groove Structure for Monitor Window Rate Uniformity
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Solution Overview
Problem
The polishing rate of wafers exhibits a significant 'jump' within +/â30 mm during chemical mechanical polishing (CMP), which is difficult to improve through pressure adjustment alone due to the limitations of the pressure adjustment zones of the polishing head.
Innovation Solution
The CMP pad incorporates monitor windows and a groove pattern structure to adjust the brush rate of the slurry, with monitor windows causing an increase and grooves causing a decrease in the brush rate, thereby compensating for the influence of monitor windows and improving polishing uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If monitor windows are introduced to enable real-time profile monitoring, then measurement precision is improved, but the brush rate of slurry increases in the monitor window influence zone causing polishing rate jump
Solution Approach 1:
The patent applies local quality by introducing a groove pattern structure specifically in the monitor window influence zone (central region of the pad), while maintaining the original surface characteristics in other areas. The grooves are configured to locally reduce slurry brush rate in the monitor window influence zone, compensating for the increased brush rate caused by monitor windows, thus achieving uniform polishing rate across the wafer surface.
2Manufacturing precision
If pressure adjustment is used to control polishing rate, then manufacturing precision is improved, but the polishing rate jump within +/â30 mm cannot be fully corrected due to pressure adjustment zone limitations
Solution Approach 1:
The groove pattern structure acts as an intermediary element between the monitor windows and the polishing process. It mediates the slurry flow dynamics in the monitor window influence zone, reducing the brush rate to compensate for the monitor window-induced increase, thereby achieving uniform polishing rate without requiring additional pressure adjustment complexity.
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
The solution effectively controls the polishing rate in the monitor window influence zone, enhancing both wafer-to-wafer and within-wafer uniformity, and allows for real-time profile monitoring and adjustment using an FVXE assembly.
Implementation Method 1
The monitor windows are connected to a light emitting apparatus and a spectrograph of an FVXE assembly through optical fibers
Implementation Method 2
a groove pattern structure which is used to adjust a brush rate of a slurry on the first surface
Implementation Method 3
The monitor windows are connected to a light emitting apparatus and a spectrograph of an FVXE assembly through optical fibers
Data Source
AI summary
The application discloses a CMP pad, comprising: a first surface and a second surface opposite to each other, the first surface being a polishing surface and being circular; and a plurality of monitor windows which penetrate through the first surface and the second surface, each of the monitor windows being uniformly distributed on a first circle, a first annular region centered on the first circle being a monitor window influence zone. The first surface is provided thereon with a groove pattern structure which is used to adjust a brush rate of a slurry on the first surface and causes a decrease in the brush rate of the slurry in the monitor window influence zone to compensate for the influence of the monitor windows on the increase in the brush rate of the slurry in the monitor window influence zone. The application also discloses CMP equipment.