Scanning Probe Stylus Integrated Base Pad Fabrication
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Solution Overview
Problem
Existing scanning probe technologies face challenges with silicon nitride tips being insufficiently sharp, limited in functionalization, and prone to thermal drift due to bimorph effects, especially when imaging in liquids, and require additional metal coatings for reflection which can compromise resolution.
Innovation Solution
The development of scanning probes with a stylus and cantilever attached via an integrated base pad, allowing for optional soft reflective coatings and enhanced tip sharpness, flexibility in chemical modification, and reduced thermal drift, using materials like silicon and carbon nanotubes, and fabrication methods that improve tip exposure and sharpness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silicon nitride tips are used, then the probe can be fabricated with integrated tip and cantilever, but the tips are insufficiently sharp for high-resolution imaging
Solution Approach 1:
The probe is divided into two separate components: a silicon cantilever assembly and a diamond tip. The diamond tip is independently synthesized on a substrate and then transferred to the cantilever, allowing each component to be optimized separately for its specific function while avoiding the manufacturing limitations of integrated silicon nitride tips
Solution Approach 2:
The probe uses a composite structure combining silicon cantilever material with diamond tip material. This composite approach leverages the mechanical flexibility of silicon for the cantilever while utilizing the extreme hardness and sharpness of diamond for the imaging tip, resolving the contradiction between ease of manufacture and tip sharpness
2Illumination intensity
If metal coatings are added to cantilever for reflection, then the probe can be used for optical detection, but the coatings compromise imaging resolution
Solution Approach 1:
The reflective coating function is extracted from the cantilever surface and relocated to a separate mirror assembly positioned near the cantilever. This allows the cantilever to remain uncoated and maintain its sharp imaging capabilities while the separate mirror provides the necessary optical reflection for detection
Solution Approach 2:
A separate mirror assembly acts as an intermediary between the uncoated cantilever and the optical detection system. This intermediary component provides the reflective surface needed for optical detection without requiring the cantilever itself to be coated, thus preserving imaging resolution
3Manufacturing precision
If silicon nitride cantilevers are used, then the probe can be fabricated with uniform thickness, but thermal drift occurs due to bimorph effects when imaging in liquids
Solution Approach 1:
The material parameter of the cantilever is changed from silicon nitride to silicon, which has different thermal and mechanical properties. Silicon cantilevers exhibit reduced thermal drift and bimorph effects when imaging in liquids, while still allowing for controlled thickness uniformity through fabrication processes
Solution Approach 2:
The probe uses a composite material strategy where the cantilever is made of silicon and the tip is made of diamond. This material combination provides thermal stability in liquid environments while maintaining the ability to fabricate uniform thickness through established silicon processing techniques
4Adaptability or versatility
If tip surface is exposed for functionalization, then chemical modification can be performed, but the tip sharpness is compromised
Solution Approach 1:
The tip structure is segmented into the imaging apex and the functionalization surface. The diamond tip provides an extremely sharp apex for imaging, while a separate portion of the tip or the cantilever surface can be exposed and functionalized without compromising the sharpness of the imaging apex
Solution Approach 2:
Different regions of the probe have different surface properties optimized for their specific functions. The tip apex maintains its natural sharp diamond surface for high-resolution imaging, while other regions of the cantilever or tip can be selectively functionalized with chemical groups for specific applications, achieving both sharpness and functionalization capability
Data Source
AI summary
The present invention is directed to scanning probes in which a cantilever contacts a stylus via an integrated stylus base pad, and methods for fabricating such probes. The probe offer many advantages over other types of scanning probes with respect to eliminating the need for a soft, reflective coating in some applications and providing for the simple fabrication of sharp stylus tips, flexibility with respect to functionalizing the tip, and minimal thermal drift due to reduced bimorph effect. The advantage of these features facilitates the acquisition of high resolution images of samples in general, and particularly in liquids.