Wafer Prober Nanosecond Pulse Testing via Direct Contact

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Solution Overview

Problem

Current wafer probing technologies are limited by long electrical connection cables, which introduce high inductance and restrict the generation of electrical pulses to microsecond ranges, potentially damaging integrated circuits during testing.

Innovation Solution

A wafer prober system that includes a chuck, a wafer carrier with protruding contact features, and a cathode plate that eliminates the need for electrical connection cables by providing a direct electrical connection between the wafer carrier and the probe card, allowing for the generation of nanosecond-range electrical pulses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If long electrical connection cables are used to connect the wafer carrier to the probe card, then the system is easier to assemble and operate, but the inductance increases and pulse width is restricted to microsecond ranges

Engineering Contradiction:

Improveease of assemblyVSAvoidinductance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent removes the electrical connection cable from the system by implementing direct contact between the cathode plate and wafer carrier contact features. This extraction of the cable eliminates the inductance problem while maintaining electrical connectivity through the direct mechanical contact of conductive surfaces.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the electrical connection function directly into the mechanical positioning structure. The cathode plate and wafer carrier contact features are designed to make direct electrical contact when the wafer carrier is positioned on the chuck, combining mechanical support and electrical connectivity into a single integrated solution.

Inventive Principle:

Principle #5Merging (Combining)

2Device complexity

If long electrical connection cables are used, then the system structure is simpler, but the transmission path length increases and causes overheating and damage to integrated circuits

Engineering Contradiction:

Improvesystem structureVSAvoidoverheating and damage

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The cable is completely removed from the system. The electrical connection is established through direct contact between the cathode plate and the wafer carrier contact features, eliminating the transmission path that would otherwise be occupied by the cable and its associated inductance and heat generation problems.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The contact features on the wafer carrier and the cathode plate serve as intermediary conductive elements that establish direct electrical connection without requiring a cable. This intermediary contact mechanism provides a low-inductance path for current flow, preventing overheating and damage to the integrated circuits.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If direct contact between cathode plate and wafer carrier is implemented, then inductance is reduced and nanosecond pulses can be generated, but the system requires precise positioning and alignment

Engineering Contradiction:

ImproveinductanceVSAvoidpositioning precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The cathode plate and wafer carrier contact features are designed to establish equipotential contact when the wafer carrier is positioned on the chuck. The contact features are arranged and dimensioned to ensure that when the wafer carrier rests on the chuck, the cathode plate makes reliable electrical contact with the contact features without requiring high-precision active positioning during operation.

Inventive Principle:

Principle #12Equipotentiality

Solution Approach 2:

The system uses the wafer carrier's own weight and positioning on the chuck to automatically establish the electrical connection. When the wafer carrier is placed on the chuck, gravity and mechanical positioning cause the cathode plate to contact the contact features, creating the electrical connection without requiring additional actuators or precision control systems.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS11181572B2Wafer prober to facilitate testing of a wafer using nanosecond pulses

Publication Date: 2021.11.23 WELLS FARGO BANK NA

AI summary

A wafer testing system may comprise a chuck, a wafer carrier, a cathode plate, and a probe card. The chuck may be configured to hold the wafer carrier. The wafer carrier may be configured to hold a wafer on a surface of the wafer carrier, wherein the surface of the wafer carrier comprises one or more contact features protruding from the surface of the wafer carrier. The cathode plate may be configured to provide an electrical connection between the wafer carrier and the probe card, wherein a portion of a surface of the cathode plate is configured to be disposed on the one or more contact features of the wafer carrier. The probe card may be configured to test, using one or more probes associated with the probe card, the wafer when the wafer is on the surface of the wafer carrier.