Polishing Pad Shaping for Semiconductor Wafer Flatness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor wafer polishing methods face challenges in achieving desired flatness due to droop at the outer periphery and irregularities at the center of the wafer, despite adjustments in carrier thickness and surface pressure distribution.
Innovation Solution
A semiconductor wafer polishing method that reverses the shape of the polished surfaces to form a shaping surface on a polishing pad shaping jig, which is then used to shape the polishing pads, optimizing surface pressure and improving flatness by transferring this shape to the wafer, with a hard coating layer for wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the thickness of the carrier is adjusted to match the target value of the final thickness of the semiconductor wafer, then droop at the outer periphery is prevented, but the center of the polished semiconductor wafer may become concave or convex due to the shape of surface plates or applied state of polishing pads, deteriorating flatness
Solution Approach 1:
The polishing pad shaping jig is used in advance to shape the polishing pads before they are applied to the semiconductor wafer. The jig creates a predetermined shape on the polishing pad surface that compensates for potential center depression or expansion, ensuring uniform surface pressure distribution during the polishing process and achieving the desired flatness
Solution Approach 2:
The polishing pad shaping jig applies different shapes to different regions of the polishing pad surface. The jig creates a non-uniform pressure distribution pattern that is specifically designed to compensate for local variations in the polishing process, such as center depression or edge droop, by applying greater pressure to specific areas
2Shape
If the surface pressure acting on the outer periphery of the semiconductor wafer is distributed from the polishing pads over the carrier, then droop at the outer periphery is prevented, but irregularities at the center of the wafer occur due to the shape of surface plates or applied state of polishing pads
Solution Approach 1:
The polishing pad shaping jig is used in advance to shape the polishing pads before they are applied to the semiconductor wafer. The jig creates a predetermined shape on the polishing pad surface that compensates for potential center depression or expansion, ensuring uniform surface pressure distribution during the polishing process and achieving the desired flatness
Solution Approach 2:
The polishing pad shaping jig changes the physical parameters of the polishing pad surface by creating a predetermined shape with specific curvature and pressure distribution characteristics. This shaped polishing pad then applies optimized surface pressure during the polishing process to achieve uniform flatness across the entire wafer surface
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 method achieves improved flatness of semiconductor wafers by ensuring uniform surface pressure distribution, reducing center depression or expansion, and enhancing the accuracy of the polished surface shape, resulting in preferable flatness values.
Implementation Method 1
polishing surfaces to be polished of a semiconductor wafer by polishing pads through relative movement between the polishing pads and the semiconductor wafer
Data Source
Figure 1~2
Figure 3~5
Figure 6-A~7
AI summary
Disclosed is a semiconductor wafer polishing method for polishing the surfaces to be polished of semiconductor wafers by use of polishing pads (16, 17) provided on fixing plates by relative movement of the polishing pads and the semiconductor wafers held by carriers. The shaping surfaces (25) of a polishing pad shaping jig (21) are shaped by inserting, with respect to ideal shapes, the shapes of the surfaces to be polished of each semiconductor wafer when the surfaces are polished by use of the polishing pads (16, 17) before shaping, and the shapes of the shaping surfaces of the polishing pad shaping jig are transferred to the pad surfaces (16A and 17A) of the respective polishing pads (16, 17). The surfaces to be polished of each semiconductor wafer are polished by use of the pad surfaces.