Wafer Inspection Probe Card with Compressed Conductive Capsules
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Solution Overview
Problem
Existing probe cards for wafer inspection face challenges in achieving stable electrical connections and preventing positional deviation due to thermal expansion differences between silicon wafers and anisotropically conductive elastomer sheets, especially when dealing with large wafer diameters and small electrode pitches, leading to increased production costs and reduced inspection efficiency.
Innovation Solution
A probe member comprising a sheet-like probe with a metal frame plate and contact films supported by a flexible insulating film, and an anisotropically conductive connector with elastic films, where the conductive parts are compressed to ensure reliable electrical contact and minimize thermal expansion effects, allowing for stable connections even on large wafers with small electrode pitches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an anisotropically conductive elastomer sheet is used to connect a large number of electrodes, then inspection efficiency is improved, but positional deviation occurs due to thermal expansion differences
Solution Approach 1:
The patent changes the physical state of the conductive material from a solid elastomer sheet to a compressed powder-filled capsule structure. This parameter change allows the conductive material to be compressed to high density, improving electrical contact while the capsule structure provides thermal expansion compensation, resolving the contradiction between connection reliability and thermal stability.
Solution Approach 2:
The patent creates a composite structure by enclosing conductive powder particles within an elastomeric capsule. This composite material combines the electrical conductivity of the powder with the elastic and thermal expansion properties of the capsule, enabling both reliable electrical connection and compensation for thermal expansion differences between the probe card and wafer.
2Productivity
If the pitch between electrodes is reduced to inspect more circuits, then inspection coverage is improved, but manufacturing difficulty increases
Solution Approach 1:
The patent replaces expensive, difficult-to-manufacture solid anisotropically conductive elastomer sheets with a simpler, more cost-effective capsule structure filled with conductive powder. This approach significantly reduces manufacturing complexity and cost, enabling the production of probe cards with fine-pitch electrode patterns that can inspect a larger number of circuits.
Solution Approach 2:
The patent uses a flexible elastomeric capsule shell to contain the conductive material. This flexible structure can conform to fine-pitch electrode patterns and provides elastic contact pressure, enabling reliable electrical connection even when the pitch between electrodes is reduced to increase inspection coverage.
3Manufacturing precision
If conductive parts are made finer to match small electrode pitches, then connection precision is improved, but production yield decreases
Solution Approach 1:
The patent extracts the conductive material from a continuous elastomer matrix and separates it into discrete powder particles enclosed in capsules. This extraction allows the conductive material to be applied as a powder fill, which can be precisely distributed to match fine electrode pitches without the manufacturing complexity and low yield associated with creating fine solid conductive structures.
Solution Approach 2:
The patent changes the form factor of the conductive material from solid continuous structures to compressed powder particles. This parameter change enables the conductive material to achieve fine dimensions with high precision while maintaining high production yield, as powder filling is a more scalable and less defect-prone manufacturing process than creating fine solid structures.
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 ensures reliable and stable electrical connections to wafers with large diameters and small electrode pitches, preventing positional deviation and reducing production costs by effectively compressing conductive parts and controlling thermal expansion, thus enhancing inspection efficiency.
Implementation Method 1
an anisotropically conductive connector, which is composed of a frame plate, in which a plurality of openings have been formed corresponding to the electrode regions, and a plurality of elastic anisotropically conductive films arranged on and supported by the frame plate so as to close the respective openings
Implementation Method 2
When a wafer that is an object of inspection is of a large size as at least 8 inches in diameter, and the number of electrodes to be inspected thereof is at least 5,000, particularly at least 10,000, however, a pitch between the electrodes to be inspected in each integrated circuit is extremely small, so that the anisotropically conductive elastomer sheet in the above probe card involves the following problems
Data Source
AI summary
A probe member for wafer inspection having a sheet-like probe, the probe including a frame plate in which openings are formed, and contact films arranged on a front surface of the frame plate so as to close the openings, each of the contact films obtained by arranging, in an insulating film formed of a flexible resin, a plurality of electrode structures, and an anisotropically conductive connector, which is composed of a frame plate, in which a plurality of openings have been formed corresponding to the electrode regions, and a plurality of elastic anisotropically conductive films arranged on and supported by the frame plate so as to close the respective openings, wherein each of the openings of the frame plate in the sheet-like probe have a size for receiving the external shape in a plane direction in the elastic anisotropically conductive film of the anisotropically conductive connector.