Sheet-like Probe With Tapered Electrodes for Fine Pitch Wafer Testing
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Solution Overview
Problem
Existing sheet-like probes face challenges in achieving stable electrical connections for circuit devices with small electrode pitches due to variations in electrode height and pitch, leading to issues like electrode slipping and reduced durability, and they struggle with maintaining a high concave and convex absorbing ability, especially when dealing with wafers of large diameters and small electrode pitches.
Innovation Solution
A sheet-like probe design featuring an insulating layer with a small thickness and electrode structures having a tapered surface electrode portion with a larger base diameter, a thicker short circuit portion, and a movable short circuit portion to prevent slipping and ensure stable connections, along with a manufacturing method using laminated resin layers with different etching speeds to control the thickness and structure of the electrode and insulating layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the insulating layer thickness is reduced to improve flexibility and concave-convex absorbing ability, then the probe can better adapt to wafer warpage and small electrode pitches, but the electrode structures may slip from the insulating layer, reducing durability
Solution Approach 1:
The invention forms protrusions on the insulating layer surface before inserting the electrode structures, creating pre-formed retention features that prevent slipping. This preliminary action ensures that when the insulating layer is made thin for flexibility, the electrode structures still have adequate mechanical retention without requiring excessive thickness
Solution Approach 2:
The insulating layer is designed with localized protrusions at specific positions where electrode structures are inserted. These protrusions create local mechanical interlocking features, allowing the overall insulating layer to remain thin for flexibility while providing localized retention points that prevent electrode slipping
2Reliability
If the electrode structures are made with larger base diameter to prevent slipping, then the durability is improved, but the pitch between adjacent electrodes increases, making it difficult to inspect small pitch circuits
Solution Approach 1:
Protrusions are formed on the insulating layer before electrode insertion, creating pre-formed mechanical retention features. This allows the electrode base diameter to remain small for fine pitch applications while the protrusions provide the necessary anti-slip functionality, resolving the contradiction between small size and stability
3Manufacturing precision
If the short circuit portion thickness is increased to improve electrical connection stability, then the manufacturing precision is improved, but the overall electrode structure height increases, reducing flexibility for adapting to wafer warpage
Solution Approach 1:
The electrode structure is designed with non-uniform thickness distribution: the short circuit portion has sufficient thickness for stable electrical connections, while the surface electrode portion has smaller diameter for fine pitch. This local differentiation allows each part to optimize its function without compromising overall flexibility
Solution Approach 2:
The invention addresses electrical connection stability not by uniformly increasing the entire electrode height, but by optimizing the short circuit portion thickness specifically. This dimensional differentiation allows the electrode to maintain flexibility in the insulating layer while ensuring stable electrical connections through the optimized short circuit portion
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 enables reliable stable electrical connections for circuit devices with small electrode pitches, prevents electrode slipping, and enhances the concave and convex absorbing ability of the probe card, improving durability and inspection efficiency.
Implementation Method 1
an anisotropically conductive sheet disposed on a surface of the circuit board for an inspection and a sheet-like probe in which a plurality of electrode structures extended to penetrate in a direction of a thickness thereof is arranged in a flexible insulating sheet
Implementation Method 2
The anisotropically conductive sheet 80 has a pressurizing conducting portion exhibiting a conductivity in only a direction of a thickness or exhibiting the conductivity in only the direction of the thickness when a pressurization is carried out in the direction of the thickness
Data Source
AI summary
A sheet-like probe and a method of producing the probe. In the probe electrode structure bodies do not come out from an insulation film and achieve high durability, and in a burn-in test for a wafer having a large area and for a circuit device having to-be-inspected electrodes with small intervals, positional displacement, caused by temperature variation, between the electrode structure bodies and the to-be-inspected electrode can be reliably prevented for stable connection conditions. The sheet-like probe includes an insulation layer and a contact film provided with electrode structure bodies arranged on the insulation layer to be apart from each other in the surface direction of the insulation layer and penetratingly extend in the thickness direction of the insulation layer. The electrode structure bodies each are composed of a surface electrode section exposed to the front surface of the insulation layer.