Modular Probe Rail Positioning for Stable Wafer Testing
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Solution Overview
Problem
Existing semiconductor probe positioning mechanisms face challenges in achieving precise positioning over a wide temperature range, particularly with smaller contact pads, due to issues like mechanical perturbations, stiffness limitations, and thermal drift, which can cause probes to miss or damage pads.
Innovation Solution
A multi-site precision positioning mechanism with modular components, including a kinematic design that provides exact constraints and high rigidity, allowing for fine alignment and minimal thermal perturbations, enabling precise positioning of multiple probe arrays across a wide temperature range while maintaining mechanical stability and allowing for easy access to probe modules in densely packed arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If linear bearing trucks and rails are used for site/rail positioning, then positioning capability is provided, but stiffness is limited due to elastic preload
Solution Approach 1:
The patent replaces the mechanical linear bearing truck and rail system with a direct kinematic mounting system. Sites are mounted directly to the rail using kinematic interfaces (such as vee-blocks and locating pins) that provide rigid mechanical support without elastic preloads. This substitution eliminates the compliance introduced by bearing trucks while maintaining positioning capability through the kinematic constraints.
2Ease of repair
If tilting of rail is used to access probe cards, then probe card replacement is enabled, but space requirements increase causing rail deflection
Solution Approach 1:
Instead of tilting the rail to access probe cards from the side, the patent inverts the approach by providing direct vertical access to probe cards from above. The probe cards are accessible through the top of the rail assembly, eliminating the need for rail tilting and the associated space requirements that cause deflection in closely-spaced arrays.
3Manufacturing precision
If fine positioning mechanism height is increased for adjustment capability, then positioning precision is improved, but microscope working distance is limited
Solution Approach 1:
The patent repositions the fine positioning mechanism to operate in a different spatial dimension. Instead of vertical adjustments that increase height and reduce working distance, the fine positioning is achieved through lateral adjustments of the site assembly on the rail, combined with rotational adjustments about vertical axes. This dimensional change maintains positioning precision while preserving adequate microscope working distance.
4Measurement precision
If crossed rods are used for XY position determination, then site positioning is achieved, but site crosstalk occurs making fine adjustment tedious
Solution Approach 1:
The patent segments the positioning system into independent axes with dedicated adjustment mechanisms. Instead of using crossed rods where X and Y positions are coupled through the rod intersections, each axis has its own independent positioning mechanism. This segmentation eliminates site crosstalk and allows straightforward, non-iterative fine adjustments along each axis without affecting the other.
Data Source
AI summary
The systems, apparatuses, and methods herein can provide a multi-site positioning mechanism suitable for long-term testing of a device(s) under test (DUT) (e.g. semiconductor wafers) across a range of temperatures with or without a controlled environment. The systems, apparatuses, and methods herein include mounting components, mechanisms, and structures that can provide excellent mechanical stability, permit relatively close working distance optics with high resolution, enable fine positioning at elevated temperature in a controlled environment with minimal thermal perturbation. The systems, apparatuses, and methods herein can be provided with modularity, for example as modular with rails and test sites that can be easily added or removed, and that can permit access to probe modules in a densely packed array.