Capacitive Probe Testing for Electronic Device Terminals
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Solution Overview
Problem
The existing probe testing methods for electronic devices suffer from electrical discontinuities, terminal deterioration, and mechanical alignment challenges, leading to reduced yield and reliability, especially when retesting is required, and can cause issues during bonding processes due to invasive nature and close terminal spacing.
Innovation Solution
The solution involves using electrically insulated test probes that couple with terminals as capacitors, allowing electro-magnetic signal transmission without direct contact, reducing terminal deterioration and improving bonding reliability through capacitive coupling, which can be achieved with conductive probes and dielectric spacers or layers to maintain signal integrity and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct contact probing is used to test electronic devices, then electrical connection for testing is achieved, but electrical discontinuity and terminal deterioration occur
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the conductive probe and the terminal. This dielectric layer prevents direct contact while allowing capacitive coupling, thereby eliminating terminal deterioration and electrical discontinuity issues associated with direct mechanical contact probing
Solution Approach 2:
The mechanical contact-based electrical connection is replaced with a capacitive coupling system. Instead of relying on physical contact between probe and terminal, the system uses electromagnetic field coupling through the dielectric layer, eliminating mechanical wear and contact resistance problems
2Productivity
If probe cards are used to test multiple terminals, then testing coverage is improved, but alignment precision and manufacturing complexity increase due to close terminal spacing
Solution Approach 1:
The dielectric layer acts as a compliant intermediary that can accommodate minor misalignments between probes and terminals. Its flexible nature allows the system to maintain capacitive coupling even when alignment is not perfectly precise, reducing the stringency of alignment requirements
Solution Approach 2:
The system changes the electrical coupling parameter from direct conductive contact to capacitive coupling. This parameter change allows for greater tolerance in spatial positioning, as capacitive coupling can be maintained over a range of distances and angles that would be unacceptable for direct contact
3Adaptability or versatility
If retesting is performed on the same terminals, then production flexibility is improved, but terminal deterioration accumulates causing reliability decrease
Solution Approach 1:
The dielectric layer serves as a protective intermediary that prevents direct mechanical contact during repeated testing operations. This eliminates the cumulative deterioration that would otherwise occur with each probing cycle, allowing unlimited retesting without compromising terminal integrity or subsequent bonding reliability
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
This approach reduces signal transmission failures, increases test reliability, and enhances bonding quality by minimizing terminal damage and alignment complexities, while allowing for efficient and precise testing without the need for precise probe alignment.
Implementation Method 1
Each test probe and the corresponding terminal form a capacitor for electro-magnetically coupling the test probe with the terminal
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
An aspect of the solution according to an embodiment of the present invention proposes a test apparatus (100, 500) for executing a test of a set of electronic devices (105) having a plurality of electrically conductive terminals (115, 208, 308, 309a, 309b, 408a, 408b). The test apparatus includes a plurality of electrically conductive test probes (135) for exchanging electrical signals with the terminals, and coupling means for mechanically coupling the test probes with the electronic devices. In the solution according to an embodiment of the invention, the coupling means includes insulating means for keeping each one of at least part of the test probes electrically insulated from at least one corresponding terminal during the execution of the test. Each test probe and the corresponding terminal form a capacitor for clectro-magnctically coupling the test probe with the terminal.