Non-magnetic Prober Chuck for Magnetic Memory Leakage Testing
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Solution Overview
Problem
Conventional prober chucks for semiconductor devices are prone to magnetic interference and vibration when subjected to magnetic fields, making low leakage evaluation challenging, especially for magnetic memories like MRAM and STT-RAM, due to the use of magnetic materials in the signal and guard layers.
Innovation Solution
A prober chuck designed with non-magnetic conductive materials like gold, aluminum, and insulating materials such as ceramic for the chuck top and guard layer, respectively, to prevent magnetic interference and vibrations, while maintaining low leakage evaluation capabilities by using a non-magnetic fixing portion and a second insulating layer to secure the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If magnetic materials such as iron are used for the conductive materials constituting the signal layer and the guard layer, then cost is reduced and strength is secured, but the chuck is physically pulled by magnetic force and vibrated into a noise source when a magnetic field of 0.1 T or higher is applied, making low leakage evaluation difficult
Solution Approach 1:
The patent changes the material parameter of the chuck components from magnetic materials (iron) to non-magnetic materials (aluminum, copper, titanium, or their alloys). This parameter change eliminates the interaction with applied magnetic fields, preventing magnetic force attraction and vibration, thereby enabling accurate low leakage evaluation while maintaining cost-effectiveness and structural strength through appropriate material selection.
2Adaptability or versatility
If a magnetic field of 1 T is applied to forcibly vary the magnetization direction of the variable layer during probe test, then the magnetic memory operation can be inspected, but the chuck made of magnetic material is physically pulled and vibrated, creating noise that interferes with measurement
Solution Approach 1:
The patent changes the magnetic property parameter of the chuck materials from magnetic to non-magnetic. This allows the system to adapt to magnetic memory testing requirements by applying strong magnetic fields (1 T) without the chuck itself being affected, thereby eliminating magnetic interference and vibration noise while maintaining full testing capability.
Solution Approach 2:
The non-magnetic chuck acts as an intermediary between the magnetic field generation system and the wafer. It transmits the necessary mechanical support and positioning functions while being transparent to the magnetic field, allowing the magnetic field to pass through without being distorted or absorbed by the chuck structure itself.
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 effectively suppresses leakage currents and maintains structural integrity under magnetic fields, ensuring accurate low leakage evaluation and reducing noise sources, thus enhancing the reliability of magnetic memory testing.
Implementation Method 1
all members constituting the chuck including the chuck top and the guard layer are made of a non-magnetic material
Implementation Method 2
an insulating layer that is made of an insulating material and supports the bottom surface of the chuck top
Implementation Method 3
a chuck top that is made of a conductive material and has the wafer placed thereon
Data Source
AI summary
There is provided a prober chuck capable of carrying out low leakage evaluation on a magnetic memory under environment in which a magnetic field is applied. A prober chuck 1 for a magnetic memory retains a wafer W having a magnetic memory formed thereon. The chuck 1 includes: a chuck top 10 that is made of a conductive material and has a wafer W placed thereon; an insulating layer 11 that is made of an insulating material and is adapted to support the bottom surface of the chuck top 10; and a guard layer 12 that is made of a conductive material and is arranged under the insulating layer 11, the guard layer being insulated from the chuck top 10 via the insulating layer 11. All of the members constituting the chuck 1 including the chuck top 10 and the guard layer 12 are made of a non-magnetic material.