CMP Shaping Pattern for Curved Semiconductor Substrates
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Solution Overview
Problem
Existing methods for shaping semiconductor substrates struggle to create precise, curved shapes in the cross-sectional plane, particularly due to the difficulty in controlling etching processes which result in less deterministic curved sidewalls.
Innovation Solution
A method involving a support layer with a shaping pattern, where chemical mechanical polishing (CMP) is used to remove material differentially based on pressure applied to positive and negative features, allowing for the creation of precisely positioned and dimensioned curved shapes by varying the thickness of the shaping layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If etching process is used to generate curved shapes, then curved sidewalls can be created, but control of the etching process is difficult and precise location and shape are problematic
Solution Approach 1:
A shaping layer is introduced as an intermediary element between the support layer and the substrate. This shaping layer with varying thickness acts as a template that mediates the CMP process to achieve precise curved shapes. The shaping layer thickness profile directly controls the pressure distribution during CMP, enabling deterministic curved sidewall formation without the control difficulties of direct etching
Solution Approach 2:
The invention replaces the chemical etching process with a mechanical CMP process. Instead of using chemical reactions to remove material and create curved shapes, a polishing head applies mechanical pressure through a shaping layer to selectively remove substrate material. This substitution provides better control over curved shape formation because the pressure distribution can be precisely engineered through the shaping layer thickness profile
2Shape
If DRIE process is used, then steep sidewalls are achieved which minimize device footprint, but curved shapes in cross sectional plane are constrained
Solution Approach 1:
The shaping layer is designed with spatially varying thickness to create different pressure zones during CMP. By making different regions of the shaping layer thicker or thinner, the invention achieves local quality control - some areas produce steep sidewalls while other areas produce curved profiles. This allows a single process to generate multiple shape types with different characteristics in different locations on the substrate
Solution Approach 2:
The invention introduces dynamic control over the CMP process by using a shaping layer with a thickness gradient. Instead of a static, uniform polishing contact, the varying shaping layer thickness creates a dynamic pressure distribution that can be optimized for different curved shape requirements. This dynamic approach enables versatile shape generation including but not limited to steep sidewalls
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
Enables the formation of substrates with controlled curved shapes in the cross-sectional plane, achieving precise thickness and shape variations, which is not easily attainable with traditional etching methods.
Implementation Method 1
performing a first chemical mechanical polishing (CMP) process on the substrate positioned on the first shaping pattern
Implementation Method 2
generating first pressure at a first location on an upper surface of the substrate as a result of the first shaping pattern, generating a second pressure at a second location on the upper surface of the substrate as a result of the first shaping pattern
Data Source
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Figure 3
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AI summary
A method of shaping a substrate in one embodiment includes providing a first support layer, providing a first shaping pattern on the first support layer, providing a substrate on the first shaping pattern, performing a first chemical mechanical polishing (CMP) process on the substrate positioned on the first shaping pattern, and removing the once polished substrate from the first shaping pattern.